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Amitrole

PubChem CID
1639
Structure
Amitrole_small.png
Amitrole_3D_Structure.png
Molecular Formula
Synonyms
  • Amitrole
  • 3-amino-1,2,4-triazole
  • 61-82-5
  • 4H-1,2,4-triazol-3-amine
  • 1H-1,2,4-Triazol-5-amine
Molecular Weight
84.08 g/mol
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Dates
  • Create:
    2004-09-16
  • Modify:
    2025-01-18
Description
Amitrole can cause cancer according to an independent committee of scientific and health experts.
Amitrole appears as odorless white crystals or white powder. Bitter taste. Melting point 147-159 °C. Sublimes undecomposed at reduced pressure. Used as a post-emergence herbicide.
Amitrole is a member of the class of triazoles that is 1H-1,2,4-triazole substituted by an amino group at position 3. Used to control annual grasses and aquatic weeds (but not on food crops because it causes cancer in laboratory animals). Its use within the EU was banned from September 2017 on the grounds of potential groundwater contamination and risks to aquatic life; there have also been concerns about its endocrine-disrupting properties. It has a role as a herbicide, an EC 1.11.1.6 (catalase) inhibitor and a carotenoid biosynthesis inhibitor. It is an aromatic amine and a member of triazoles.

1 Structures

1.1 2D Structure

Chemical Structure Depiction
Amitrole.png

1.2 3D Conformer

1.3 Crystal Structures

COD records with this CID as component

2 Names and Identifiers

2.1 Computed Descriptors

2.1.1 IUPAC Name

1H-1,2,4-triazol-5-amine
Computed by Lexichem TK 2.7.0 (PubChem release 2021.10.14)

2.1.2 InChI

InChI=1S/C2H4N4/c3-2-4-1-5-6-2/h1H,(H3,3,4,5,6)
Computed by InChI 1.0.6 (PubChem release 2021.10.14)

2.1.3 InChIKey

KLSJWNVTNUYHDU-UHFFFAOYSA-N
Computed by InChI 1.0.6 (PubChem release 2021.10.14)

2.1.4 SMILES

C1=NNC(=N1)N
Computed by OEChem 2.3.0 (PubChem release 2024.12.12)

2.2 Molecular Formula

C2H4N4
Computed by PubChem 2.2 (PubChem release 2021.10.14)
C2H4N4

2.3 Other Identifiers

2.3.1 CAS

61-82-5

2.3.2 Deprecated CAS

1057722-43-6, 11121-00-9, 151517-46-3, 155-25-9, 16681-74-6, 2356230-47-0, 29212-82-6, 30922-30-6, 6051-75-8, 63598-72-1, 64598-23-8
11121-00-9, 151517-46-3, 155-25-9, 16681-74-6, 29212-82-6, 30922-30-6, 6051-75-8, 63598-72-1, 64598-23-8

2.3.3 European Community (EC) Number

2.3.4 UNII

2.3.5 UN Number

2.3.6 ChEBI ID

2.3.7 ChEMBL ID

2.3.8 DSSTox Substance ID

2.3.9 HMDB ID

2.3.10 ICSC Number

2.3.11 KEGG ID

2.3.12 Metabolomics Workbench ID

2.3.13 NCI Thesaurus Code

2.3.14 Nikkaji Number

2.3.15 NSC Number

2.3.16 RTECS Number

2.3.17 Wikidata

2.3.18 Wikipedia

2.4 Synonyms

2.4.1 MeSH Entry Terms

  • 3-Amino-1,2,4-triazole
  • Aminotriazole
  • Amitrole

2.4.2 Depositor-Supplied Synonyms

3 Chemical and Physical Properties

3.1 Computed Properties

Property Name
Molecular Weight
Property Value
84.08 g/mol
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
XLogP3-AA
Property Value
-0.4
Reference
Computed by XLogP3 3.0 (PubChem release 2021.10.14)
Property Name
Hydrogen Bond Donor Count
Property Value
2
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Hydrogen Bond Acceptor Count
Property Value
3
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Rotatable Bond Count
Property Value
0
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Exact Mass
Property Value
84.043596145 Da
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
Monoisotopic Mass
Property Value
84.043596145 Da
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
Topological Polar Surface Area
Property Value
67.6 Ų
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Heavy Atom Count
Property Value
6
Reference
Computed by PubChem
Property Name
Formal Charge
Property Value
0
Reference
Computed by PubChem
Property Name
Complexity
Property Value
44.8
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Isotope Atom Count
Property Value
0
Reference
Computed by PubChem
Property Name
Defined Atom Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Undefined Atom Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Defined Bond Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Undefined Bond Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Covalently-Bonded Unit Count
Property Value
1
Reference
Computed by PubChem
Property Name
Compound Is Canonicalized
Property Value
Yes
Reference
Computed by PubChem (release 2021.10.14)

3.2 Experimental Properties

3.2.1 Physical Description

Amitrole appears as odorless white crystals or white powder. Bitter taste. Melting point 147-159 °C. Sublimes undecomposed at reduced pressure. Used as a post-emergence herbicide.
Colorless to white, crystalline powder. [herbicide] [Note: Odorless when pure.]
ODOURLESS COLOURLESS CRYSTALS.
Colorless to white, crystalline powder.

3.2.2 Color / Form

Transparent to off white crystalline powder
USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from, as of Jan 31, 2006: https://www.epa.gov/pesticides/reregistration/status.htm

3.2.3 Odor

Odorless when pure.
NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)

3.2.4 Taste

Bitter taste
IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V7: 32 (1974)

3.2.5 Melting Point

318 °F (NTP, 1992)
National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
159 °C
USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from, as of Jan 31, 2006: https://www.epa.gov/pesticides/reregistration/status.htm
MP: 150-153 °C. /TECHNICAL GRADE/
Spencer, E. Y. Guide to the Chemicals Used in Crop Protection. 7th ed. Publication 1093. Research Institute, Agriculture Canada, Ottawa, Canada: Information Canada, 1982., p. 15
MP: 153-159 °C. /TECHNICAL GRADE/
CYANAMID TECH INFORMATION SHEET FOR OF AMITROLE
318 °F

3.2.6 Solubility

7.6 [ug/mL] (The mean of the results at pH 7.4)
greater than or equal to 100 mg/mL at 63.5 °F (NTP, 1992)
National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
2.6X10+5 mg/L in ethanol at 75 °C. Slightly soluble in chloroform, acetonitrile, and ethyl acetate; and insoluble in acetone, ether, hydrocarbons
USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from, as of Jan 31, 2006: https://www.epa.gov/pesticides/reregistration/status.htm
In water, 2.8X10+5 mg/L at 25 °C
USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from, as of Jan 31, 2006: https://www.epa.gov/pesticides/reregistration/status.htm
Solubility in water, g/l at 25 °C: 280
(77 °F): 28%

3.2.7 Density

1.138 at 68 °F (NTP, 1992) - Denser than water; will sink
National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
1.138 at 20 °C
Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium, 11 th ed., British Crop Protection Council, Surrey, England 1997, p. 41
Relative density (water = 1): 1.14 (20 °C)
1.14

3.2.8 Vapor Density

Relative vapor density (air = 1): 2.9

3.2.9 Vapor Pressure

4.41e-07 mmHg at 68 °F (NTP, 1992)
National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
0.00000044 [mmHg]
4.4X10-7 mm Hg at 25 °C
USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from, as of Jan 31, 2006: https://www.epa.gov/pesticides/reregistration/status.htm
Vapor pressure, kPa at 20 °C: (negligible)
<0.000008 mmHg

3.2.10 LogP

log Kow= -0.97
Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium, 11 th ed., British Crop Protection Council, Surrey, England 1997, p. 41
-0.97

3.2.11 Stability / Shelf Life

No shelf life limitations
Weed Science Society of America. Herbicide Handbook. 5th ed. Champaign, Illinois: Weed Science Society of America, 1983., p. 21
Decomposes in the presence of light.
Spencer, E. Y. Guide to the Chemicals Used in Crop Protection. 7th ed. Publication 1093. Research Institute, Agriculture Canada, Ottawa, Canada: Information Canada, 1982., p. 15
Stable in neutral, acidic and alkaline media; DT50 >30 days (pH 4-9, 23 °C). Photolysis DT50 >30 days (pH 5-9, 25 °C). Powerful chelating agent.
Tomlin CDS, ed. Amitrole (61-82-5). In: The e-Pesticide Manual, 13th Edition Version 3.2 (2005-06). Surrey UK, British Crop Protection Council.

3.2.12 Decomposition

When strongly heated it emits highly toxic fumes of /nitrogen oxides/.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 228

3.2.13 Corrosivity

MILDLY CORROSIVE TO IRON, ALUMINUM, COPPER, & COPPER ALLOYS.
Weed Science Society of America. Herbicide Handbook. 5th ed. Champaign, Illinois: Weed Science Society of America, 1983., p. 21

3.2.14 pH

FORMS NEUTRAL AQ SOLN BUT ACTS AS WEAK BASE WITH KB OF 1X10-10
Kearney, P.C., and D. D. Kaufman (eds.) Herbicides: Chemistry, Degredation and Mode of Action. Volumes 1 and 2. 2nd ed. New York: Marcel Dekker, Inc., 1975., p. 378

3.2.15 Dissociation Constants

pKa1 = 4.2; pKa2 = 10.7
Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium, 11 th ed., British Crop Protection Council, Surrey, England 1997, p. 41

3.2.16 Kovats Retention Index

Standard non-polar
1300 , 1324

3.2.17 Other Experimental Properties

It will diazotize & couple with several dyes.
Kearney, P.C., and D. D. Kaufman (eds.) Herbicides: Chemistry, Degredation and Mode of Action. Volumes 1 and 2. 2nd ed. New York: Marcel Dekker, Inc., 1975., p. 378
Sublimes undecomposed under reduced pressure; it forms chelates with metals such as iron & copper; primary amino group reacts with acylating agents to give mono & diacyl deriv; yields aldimines or ketimines with aldehydes.
IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V7 32(1974)
1 MG/L= 291 PPM; 1 PPM= 3.44 MG/CU M
Clayton, G. D. and F. E. Clayton (eds.). Patty's Industrial Hygiene and Toxicology: Volume 2A, 2B, 2C: Toxicology. 3rd ed. New York: John Wiley Sons, 1981-1982., p. 2702

3.3 Chemical Classes

3.3.1 Endocrine Disruptors

Potential endocrine disrupting compound
S109 | PARCEDC | List of 7074 potential endocrine disrupting compounds (EDCs) by PARC T4.2 | DOI:10.5281/zenodo.10944198

3.3.2 Pesticides

Agrochemicals -> Pesticide active substances
Active substance -> EU Pesticides database: Not approved
Pesticides -> Herbicides, Other
Herbicides
S69 | LUXPEST | Pesticide Screening List for Luxembourg | DOI:10.5281/zenodo.3862688

4 Spectral Information

4.1 1D NMR Spectra

1D NMR Spectra
NMR: 9499 (Sadtler Research Laboratories Spectral Collection)

4.1.1 1H NMR Spectra

1 of 2
Instrument Name
BRUKER AC-300
Source of Sample
Tokyo Kasei Kogyo Company, Ltd., Tokyo, Japan
Copyright
Copyright © 1991-2024 John Wiley & Sons, Inc. All Rights Reserved.
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2 of 2
Instrument Name
Varian A-60
Copyright
Copyright © 2009-2024 John Wiley & Sons, Inc. All Rights Reserved.
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4.1.2 13C NMR Spectra

1 of 2
Source of Sample
Fluka AG, Buchs, Switzerland
Copyright
Copyright © 1980, 1981-2024 John Wiley & Sons, Inc. All Rights Reserved.
Thumbnail
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2 of 2
Source of Sample
Pfaltz & Bauer, Inc., Waterbury, Connecticut
Copyright
Copyright © 1980, 1981-2024 John Wiley & Sons, Inc. All Rights Reserved.
Thumbnail
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4.1.3 15N NMR Spectra

Copyright
Copyright © 2016-2024 W. Robien, Inst. of Org. Chem., Univ. of Vienna. All Rights Reserved.
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4.2 Mass Spectrometry

4.2.1 GC-MS

1 of 8
View All
Spectra ID
Instrument Type
GC-MS
Top 5 Peaks

213.0 1

99.0 0.40

171.0 0.32

214.0 0.21

228.0 0.21

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2 of 8
View All
Spectra ID
Instrument Type
GC-MS
Top 5 Peaks

285.0 1

171.0 0.38

130.0 0.29

99.0 0.29

100.0 0.28

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4.2.2 MS-MS

1 of 2
Spectra ID
Ionization Mode
Positive
Top 5 Peaks

85.0508 100

57.0449 3.22

58.0401 1.10

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2 of 2
NIST Number
1176703
Instrument Type
IT/ion trap
Collision Energy
0
Spectrum Type
MS2
Precursor Type
[M+H]+
Precursor m/z
85.0509
Total Peaks
2
m/z Top Peak
57
m/z 2nd Highest
57.7
m/z 3rd Highest
0
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4.2.3 LC-MS

1 of 31
View All
Authors
Nikiforos Alygizakis, Katerina Galani, Nikolaos Thomaidis, University of Athens
Instrument
Bruker maXis Impact
Instrument Type
LC-ESI-QTOF
MS Level
MS2
Ionization Mode
POSITIVE
Ionization
ESI
Collision Energy
Ramp 14.4-21.6 eV
Fragmentation Mode
CID
Column Name
Acclaim RSLC C18 2.2um, 2.1x100mm, Thermo
Retention Time
1.345 min
Precursor m/z
85.0509
Precursor Adduct
[M+H]+
Top 5 Peaks

85.0508 999

58.0391 467

57.0441 389

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License
CC BY
2 of 31
View All
Authors
Kevin S. Jewell; Björn Ehlig; Arne Wick
Instrument
TripleTOF 6600 SCIEX
Instrument Type
LC-ESI-QTOF
MS Level
MS2
Ionization Mode
POSITIVE
Ionization
ESI
Collision Energy
40
Fragmentation Mode
CID
Column Name
Zorbax Eclipse Plus C18 2.1 mm x 150 mm, 3.5 um, Agilent
Retention Time
1.218 min
Precursor m/z
85.0509
Precursor Adduct
[M+H]+
Top 5 Peaks

43.0293 999

42.0211 111

58.0396 75

85.0504 49

31.0292 34

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License
dl-de/by-2-0

4.2.4 Other MS

1 of 4
View All
Other MS
MASS: 59429 (NIST/EPA/MSDC Mass Spectral Database, 1990 version)
2 of 4
View All
MoNA ID
MS Category
Experimental
MS Type
Other
MS Level
MS2
Precursor Type
[M+H]+
Precursor m/z
85.05
Instrument
TQD, Waters
Instrument Type
Flow-injection QqQ/MS
Ionization
ESI
Ionization Mode
positive
Collision Energy
20
Top 5 Peaks

85 100

84 21.84

43 15.47

57 9.02

42 4.42

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4.3 UV Spectra

4.3.1 UV-VIS Spectra

1 of 2
Copyright
Copyright © 2008-2024 John Wiley & Sons, Inc. All Rights Reserved.
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2 of 2
Copyright
Copyright © 2008-2024 John Wiley & Sons, Inc. All Rights Reserved.
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4.4 IR Spectra

IR Spectra
IR: 21258 (Sadtler Research Laboratories IR Grating Collection)

4.4.1 FTIR Spectra

1 of 2
Technique
MELT
Source of Sample
Ultra Scientific, Inc.
Copyright
Copyright © 1980, 1981-2024 John Wiley & Sons, Inc. All Rights Reserved.
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2 of 2
Instrument Name
Bruker IFS 85
Technique
KBr-Pellet
Source of Sample
Ega-Chemie GmbH & Co KG, Steinheim
Copyright
Copyright © 1989, 1990-2024 Wiley-VCH Verlag GmbH & Co. KGaA. All Rights Reserved.
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4.4.2 ATR-IR Spectra

1 of 2
Instrument Name
Bio-Rad FTS
Technique
ATR-Neat (DuraSamplIR II)
Source of Spectrum
Forensic Spectral Research
Source of Sample
J. T. Baker, Mallinckrodt Baker, Inc.
Catalog Number
B312
Lot Number
2-748
Copyright
Copyright © 2009-2024 John Wiley & Sons, Inc. All Rights Reserved.
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2 of 2
Source of Sample
Aldrich
Catalog Number
A81609
Copyright
Copyright © 2018-2024 Sigma-Aldrich Co. LLC. - Database Compilation Copyright © 2018-2024 John Wiley & Sons, Inc. All Rights Reserved.
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4.4.3 Vapor Phase IR Spectra

Instrument Name
DIGILAB FTS-14
Technique
Vapor Phase
Copyright
Copyright © 1980, 1981-2024 John Wiley & Sons, Inc. All Rights Reserved.
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4.5 Raman Spectra

Technique
FT-Raman
Source of Spectrum
Forensic Spectral Research
Source of Sample
J. T. Baker, Mallinckrodt Baker, Inc.
Catalog Number
B312
Lot Number
2-748
Copyright
Copyright © 2012-2024 John Wiley & Sons, Inc. All Rights Reserved.
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6 Chemical Vendors

7 Food Additives and Ingredients

7.1 Food Additive Classes

JECFA Functional Classes
Food Contaminant -> CONTAMINANT;

7.2 Evaluations of the Joint FAO / WHO Expert Committee on Food Additives - JECFA

Chemical Name
AMINOTRIAZOLE
Evaluation Year
1960
Comments
The Committee noted that aminotriazole is reportedly goiterogenic in rodents and induces thyroid tumors in rats; the Committee noted that there was no evidence that aminotriazole is carcinogenic in humans.

8 Agrochemical Information

8.1 Agrochemical Category

Herbicide
Pesticide active substances
Herbicides
S69 | LUXPEST | Pesticide Screening List for Luxembourg | DOI:10.5281/zenodo.3862688

8.2 EU Pesticides Data

Active Substance
amitrole (aminotriazole)
Status
Not approved [Reg. (EC) No 1107/2009]
Date
Approval: 01/01/2002 Expiration: 30/06/2016
Legislation
01/21/EC, 2010/77/EU, Reg (EU) 2015/408, Reg. (EU) 2015/1885, Reg. (EU) 2016/871, Reg. (EU) No 540/2011
ADI
0.001 mg/kg bw/day [EFSA 2015]
ARfD
0.015 mg/kg bw [EFSA 2015]
AOEL
0.001 mg/kg bw/day [EFSA 2015]

9 Pharmacology and Biochemistry

9.1 MeSH Pharmacological Classification

Enzyme Inhibitors
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction. (See all compounds classified as Enzyme Inhibitors.)

9.2 Absorption, Distribution and Excretion

Aminotriazole was applied to skin of rabbits. After 15 min it had penetrated into the blood. Fat was ... /an/ inconsequential site of storage.
SHAH PV, GUTHRIE FE; IN PESTICIDE MANAGEMENT AND INSECTICIDE RESISTANCE; WATSON DL, BROWN AWA, EDS, P.547 (1976)
Wistar rats were fed 1 mg 14C-amitrole (per rat) via stomach tube. The expired air, urine, feces and tissues were analyzed for radioactivity during a three day period following dosing. During the first 24 hours, 70 to 95.5% of the radioactivity was found in the urine; a small variable amount of activity was found in the feces. After absorption, amitrole was distributed throughout most body tissues. The maximum radioactivity was found in liver and kidney. Within three to four hours of dosing, the tissue levels began decreasing. Paper chromatography revealed both unchanged amitrole and one unidentified metabolite in rat liver slices taken at various times following dosing.
USEPA; Reregistration Eligibility Decision (RED) Database for Amitrole (61-82-5). Available from, as of January 30, 2006: https://www.epa.gov/pesticides/reregistration/status.htm
Primary routes of exposure are skin, eye contact and inhalation of powders, liquids, and sprays.
Clayton, G. D. and F. E. Clayton (eds.). Patty's Industrial Hygiene and Toxicology: Volume 2A, 2B, 2C: Toxicology. 3rd ed. New York: John Wiley Sons, 1981-1982., p. 2702
Anesthetized animals were allowed to inhale through a tracheal cannula liquid aerosols of drug solutions generated with an air-jet nebulizer. The aerosols had a mass median aerodynamic diameter of 2.81 um and a geometric standard deviation of 2.53. The time necessary for 50% absorption of amitrole was 1.3 min. Comparison with previously reported absorption rates measured after intratracheal injection of 0.1 mL of drug solution showed that drug inhaled as an aerosol was absorbed roughly 2 times more rapidly than when administered by intratracheal injection.
BROWN RA JR, SCHANKER LS; DRUG METAB DISPOS 11 (4): 355-60 (1983)
For more Absorption, Distribution and Excretion (Complete) data for AMITROLE (11 total), please visit the HSDB record page.

9.3 Metabolism / Metabolites

After 39-yr-old woman ingested 20 mg/kg of aminotriazole, urine taken some hours later contained unchanged aminotriazole (100 mg/100 mL). No metabolites were found.
Menzie, C.M. Metabolism of Pesticides, Update II. U.S. Department of the Interior, Fish Wildlife Service, Special Scientific Report - Wildlife No. 2l2. Washington, DC: U.S. Government Printing Office, 1978., p. 20
Metabolism... in plants: Glycine and serin of plants are utilized in biosynthesis of beta-(3-amino-S-triazolyl-1-)alpha-alanine.
Weed Science Society of America. Herbicide Handbook. 5th ed. Champaign, Illinois: Weed Science Society of America, 1983., p. 21
In... studies with Canada thistle, 3 compounds ... observed. One was identified as beta-(3-amino-1,2,4-triazolyl-1)-alpha-alanine).
Menzie, C.M. Metabolism of Pesticides, Update II. U.S. Department of the Interior, Fish Wildlife Service, Special Scientific Report - Wildlife No. 2l2. Washington, DC: U.S. Government Printing Office, 1978., p. 20
Major metabolic product formed from amitrole by microbiological activity was carbon dioxide. ... E coli converted 3-ATA into metabolite, 3-amino-1,2,4,-triazolyl alanine.
Menzie, C.M. Metabolism of Pesticides. U.S. Department of the Interior, Bureau of Sport Fisheries and Wildlife, Publication 127. Washington, DC: U.S. Government Printing Office, 1969., p. 40
For more Metabolism/Metabolites (Complete) data for AMITROLE (10 total), please visit the HSDB record page.

9.4 Biological Half-Life

Two groups of five male and five female Sprague-Dawley rats weighing 200-250 g were exposed (either nose only or whole body) to atmospheres of 5-14C-amitrole (radiochemical purity > 97%) in water aerosols at concentrations in air of 49.2 ug/liter (2.6 uCi/liter) or 25.8 ug/liter (1.4 uCi/liter), respectively, for 1 hr, and then observed for 120 hr. The particle size distribution of the aerosols was not reported. The calculated elimination half-life of radioactivity was approximately 21 hr for both exposures; approximately 75% of the radioactivity was eliminated in the urine within 12 hr.
WHO; Environmental Health Criteria Document No. 158: Amitrole (61-82-5). Available from, as of January 30, 2006: https://www.inchem.org/pages/ehc.html
Rats (5/sex; Charles River Ltd.) were exposed by inhalation to an estimated dose of 25.8 ug/L for "whole body" or 49.2 ug/L for "head only" radiolabelled amitrole for one hour. Blood samples were taken at specified intervals and urine, feces and carcasses were examined for radioactivity. ...The blood plasma half life was estimated to be 20 hours.
USEPA; Reregistration Eligibility Decision (RED) Database for Amitrole (61-82-5). Available from, as of January 30, 2006: https://www.epa.gov/pesticides/reregistration/status.htm

9.5 Mechanism of Action

Amitrole inhibits peroxidase activity in liver & thyroids, & mode of action in producing thyroid tumors appears to be related to goitrogenic effect of amitrole with resultant increased TSH (thyroid-stimulating hormone) ... .
Doull, J., C.D.Klassen, and M.D. Amdur (eds.). Casarett and Doull's Toxicology. 3rd ed., New York: Macmillan Co., Inc., 1986., p. 559
This study demonstrated that the compound 3-amino-1,2,4-triazole is a strong inhibitor of erythrocyte glutathione peroxidase activity. Moreover, 3-amino-1,2,4-triazole inhibits arachidonic-induced malondialdehyde formation in platelet-rich plasma and prostacyclin-like activity generation in aorta rings. These results give new lines of evidence on the connection between glutathione peroxidase activity and prostaglandin synthesis in rat platelets and arterial vessel walls.
DONI MG, PIVA E; HAEMOSTASIS 13 (4): 240-3 (1983)
A technique for the cytochemical demonstration of peroxidase activity in unfixed guinea-pig thyroid tissue is described. Both 3-amino-1,2,4-triazole and methimazole inhibited peroxidase activity in the follicle cells (enzyme activity was still seen in the erythrocytes), maximal inhibition occurring at 10 mmol.
EALEY PA ET AL; HISTOCHEM J 16 (2): 111-22 (1984)
Interference with histidine metabolism, inhibition of pigment biosynthesis, or both have been the principal candidates for the primary site of action of 3-amino-1,2,4-triazole (amitrole). Arabidopsis thaliana is sensitive to 1,2,4-triazole-3-alanine, a feedback inhibitor of histidine biosynthesis, and this effect is reversed by histidine. The combination of triazolealanine and histidine, however, does not reverse the herbicical effect of amitrole. This indicates that amitrole toxicity is not caused by histidine starvation, nor is it caused by the accumulation of a toxic intermediate of the histidine pathway. Amitrole inhibits root elongation at lower concentrations than it causes pigment bleaching in the leaves. In contrast, fluridone, a known inhibitor of the carotenoid biosynthetic pathway does not block root elongation. Fluridone also inhibits carotenoid accumulation in etiolated seedlings in the dark, but amitrole does not. Last, gabaculine and acifluorfen, but not amitrole, prevent chlorophyll accumulation in greeting etiolated seedlings of Arabidopsis. ...
Heim DR, Larrinua IM; Plant Physiol 91 (3): 1226-31 (1989)
For more Mechanism of Action (Complete) data for AMITROLE (8 total), please visit the HSDB record page.

10 Use and Manufacturing

10.1 Uses

EPA CPDat Chemical and Product Categories
The Chemical and Products Database, a resource for exposure-relevant data on chemicals in consumer products, Scientific Data, volume 5, Article number: 180125 (2018), DOI:10.1038/sdata.2018.125
Sources/Uses
Used control grasses, broadleafs, poison ivy, and aquatic weeds. [EXTOXNET]
Restricted Notes
Use on food crops was canceled by the EPA in 1971; [EXTOXNET]
For 2-amino-1,3,4-triazole (USEPA/OPP Pesticide Code: 004401) ACTIVE products with label matches. /SRP: Registered for use in the U.S. but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./
National Pesticide Information Retrieval System's USEPA/OPP Chemical Ingredients Database on 3-Amino-1,2,4-triazole (61-82-5). Available from, as of January 23, 2006: https://npirspublic.ceris.purdue.edu/ppis/
Broadleaf weeds, annual grasses, poison ivy in noncropland; semi-aquatic weeds in marshes, drainage ditches.
Crop Protection Handbook 2005. (Formerly Farm and Chemicals Handbook) Willoughby, OH: Meister Publishing Co., 2005., p. D-20
/Herbicide/ for perennial broadleaf weeds & grasses in non-cropped areas ... some aquatic weeds ... . Used in mixture with more persistent herbicides for general weed control in non-cropped areas & as directed spray in ornamental nurseries.
Weed Science Society of America. Herbicide Handbook. 4th ed. Champaign, IL: Weed Science Society of America, 1979. of America, 1979., p. 18
... Plant growth regulator; feedstock for chemical synthesis
Verschueren, K. Handbook of Environmental Data on Organic Chemicals. Volumes 1-2. 4th ed. John Wiley & Sons. New York, NY. 2001, p. 183
/Amitrole/ is effective in killing mostly woody plants, including hardwood and coniferous species.
Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. 4:1160

10.1.1 Use Classification

Food Contaminant -> CONTAMINANT; -> JECFA Functional Classes
Hazard Classes and Categories -> Carcinogens
Herbicides
S69 | LUXPEST | Pesticide Screening List for Luxembourg | DOI:10.5281/zenodo.3862688

10.2 Methods of Manufacturing

Allen, US 2670282 (1954 to American Chemical Paint co.)
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. 13th Edition, Whitehouse Station, NJ: Merck and Co., Inc., 2001., p. 86
Reaction of aminoguanidine with formic acid.
SRI
From formylguanine nitrate & sodium carbonate; heating s-triazine to 120 °C in presence of aminoguanidine.
Kearney, P.C., and D. D. Kaufman (eds.) Herbicides: Chemistry, Degredation and Mode of Action. Volumes 1 and 2. 2nd ed. New York: Marcel Dekker, Inc., 1975., p. 379
Cyclization /of aminoguanidine/ with formic acid produces 3-amino-1,2,4-triazole
Ullmann's Encyclopedia of Industrial Chemistry. 6th ed.Vol 1: Federal Republic of Germany: Wiley-VCH Verlag GmbH & Co. 2003 to Present, p. V16 80 (2003)
Amitrole is synthesized by condensing formic acid with aminoguanidine and can be purified by recrystallization from methanol.
Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. 4:1160

10.3 Formulations / Preparations

Amizine is trade name for mixture of amitrole & simazine ... and fenamine refers to combination of amitrole, fenac & atrazine.
Kearney, P.C., and D. D. Kaufman (eds.) Herbicides: Chemistry, Degredation and Mode of Action. Volumes 1 and 2. 2nd ed. New York: Marcel Dekker, Inc., 1975., p. 379
... Kleer-lot (mixture of amitrole & linuron) ... .
Weed Science Society of America. Herbicide Handbook. 4th ed. Champaign, IL: Weed Science Society of America, 1979. of America, 1979., p. 18
Amino triazole weedkiller 90 is dry soluble powder formulation containing 90% active ingredient. Cytrol amitrole-t liquid weedkiller is water soluble formulation containing 2 lbs amino triazole plus 19% ammonium thiocyanate/gal.
AMERICAN CYANAMID CO TECHNICAL INFORMATION ON AMINO TRIAZOLE WEEDKILLER 90
Pure, technical grades
CHEMCYCLOPEDIA 1987 p.262
For more Formulations/Preparations (Complete) data for AMITROLE (9 total), please visit the HSDB record page.

10.4 Consumption Patterns

HERBICIDE FOR INDUSTRIAL/COMMERCIAL USES, 86%, AQUATIC USES, 14% (1982)
SRI

10.5 U.S. Production

(1978) NOT PRODUCED COMMERCIALLY IN USA
SRI
(1982) NOT PRODUCED COMMERCIALLY IN USA
SRI
(1990) 10 thousand-500 thousand pounds
US EPA; Non-confidential Production Volume Information Submitted by Companies for Chemicals Under the 1986-2002 Inventory Update Rule (IUR). 1H-1,2,4-Triazol-3-amine (61-82-5). Available from, as of January 19, 2006: https://www.epa.gov/oppt/iur/tools/data/2002-vol.html

10.6 U.S. Imports

(1978) 5.38X10+8 G
SRI
(1982) 2.11X10+8 G
SRI
(1985) 2.63X10+8 G
BUREAU OF THE CENSUS. U.S. IMPORTS FOR CONSUMPTION AND GENERAL IMPORTS 1985 p.1-575

10.7 General Manufacturing Information

EPA TSCA Commercial Activity Status
Foliage spray on weeds. Rates: 2 to 10 lb/acre. Usual carrier: water--20 to 200 gal/acre; water-soluble. /Former use/
Weed Science Society of America. Herbicide Handbook. 4th ed. Champaign, IL: Weed Science Society of America, 1979. of America, 1979., p. 19
Suitable for use with hard water. Not intended for mixing with other pesticides & fertilizers.
Weed Science Society of America. Herbicide Handbook. 4th ed. Champaign, IL: Weed Science Society of America, 1979. of America, 1979., p. 19
All registered uses of amitrole on food crops were cancelled in 1971 /in USA/.
Kearney, P.C., and D. D. Kaufman (eds.) Herbicides: Chemistry, Degredation and Mode of Action. Volumes 1 and 2. 2nd ed. New York: Marcel Dekker, Inc., 1975., p. 378
Not registered for use on food crops. ... Industrial areas (outdoor), non-agricultural rights-of-way/fence rows/ hedge rows, non-agricultural uncultivated areas/soils, ornamental and/or shade trees, ornamental shrubs and vines.
USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from, as of Jan 31, 2006: https://www.epa.gov/pesticides/reregistration/status.htm

11 Identification

11.1 Analytic Laboratory Methods

Residue method sensitive to 0.1 ug for determination of amitrole in sugarcane or concn samples of juice is available.
Weed Science Society of America. Herbicide Handbook. 4th ed. Champaign, IL: Weed Science Society of America, 1979. of America, 1979., p. 20
Micro: extract soil with water, add sodium nitroprusside reagent and measure green color at 634 nm . ... in crops: ... /spectrophotometry/ at 455 nm.
Spencer, E. Y. Guide to the Chemicals Used in Crop Protection. 7th ed. Publication 1093. Research Institute, Agriculture Canada, Ottawa, Canada: Information Canada, 1982., p. 15
Determination of amitrole in soil samples by liq & tlc discussed. Dansylation of amitrole, several possibilities of its liq chromatographic separation from other herbicides & typical UV & mass spectra presented.
PRIBYL J ET AL; FRESENIUS Z ANAL CHEM 289 (2): 81 (1978)
High performance liquid chromatography/ultra violet detection is used for determination of amitrole in soil and vine leaves. Limit of detection is 0.17 ug/ml.
IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V41 298 (1986)
For more Analytic Laboratory Methods (Complete) data for AMITROLE (7 total), please visit the HSDB record page.

11.2 Clinical Laboratory Methods

High performance liquid chromatography/visible spectrophotometric detection, at a wavelength of 440 nm is used for determination of amitrole in urine. Limit of detection is 200 ug/l.
IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V41 298 (1986)
Amitrol in urine is separated by paper chromatography using phenol saturated with water or a mixture of n-butanol: water (15:1) and propionic acid: Water (7:6) and is identified by spraying with a solution of P-dimethylaminobenzaldehyde in acetic acid or hydrochloric acid.
IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V7 31(1974)

12 Safety and Hazards

12.1 Hazards Identification

12.1.1 GHS Classification

1 of 5
View All
Pictogram(s)
Health Hazard
Environmental Hazard
Signal
Warning
GHS Hazard Statements

H361 (97.6%): Suspected of damaging fertility or the unborn child [Warning Reproductive toxicity]

H373 (98.8%): May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure]

H411 (99.4%): Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

Precautionary Statement Codes

P203, P260, P273, P280, P318, P319, P391, P405, and P501

(The corresponding statement to each P-code can be found at the GHS Classification page.)

ECHA C&L Notifications Summary

Aggregated GHS information provided per 170 reports by companies from 15 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown.

12.1.2 Hazard Classes and Categories

Repr. 2 (97.6%)

STOT RE 2 (98.8%)

Aquatic Chronic 2 (99.4%)

Reproductive toxicity - category 2

Specific target organ toxicity (repeated exposure) - category 2

Hazardous to the aquatic environment (chronic) - category 2

12.1.3 NFPA Hazard Classification

NFPA 704 Diamond
1-1-0
NFPA Health Rating
1 - Materials that, under emergency conditions, can cause significant irritation.
NFPA Fire Rating
1 - Materials that must be preheated before ignition can occur. Materials require considerable preheating, under all ambient temperature conditions, before ignition and combustion can occur.
NFPA Instability Rating
0 - Materials that in themselves are normally stable, even under fire conditions.

12.1.4 Health Hazards

Excerpt from NIOSH Pocket Guide for Amitrole:

Exposure Routes: Inhalation, ingestion, skin and/or eye contact

Symptoms: Irritation eyes, skin; dyspnea (breathing difficulty), muscle spasms, ataxia, anorexia, salivation, increased body temperature; lassitude (weakness, exhaustion), skin dryness, depression (thyroid function suppression)

Target Organs: Eyes, skin, thyroid

Cancer Site: [in animals: liver, thyroid & pituitary gland tumors] (NIOSH, 2024)

12.1.5 Fire Hazards

Literature sources indicate that this compound is non-combustible. (NTP, 1992)
National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
Combustible if powdered. Gives off irritating or toxic fumes (or gases) in a fire.

12.1.6 Hazards Summary

In the triazole class of herbicides, the known toxicity of amitrole is limited to slight irritant effects. [EPA Pesticides, p. 121] Classified as slightly toxic, it may be used only by certified applicators. [EXTOXNET] A weed control worker with allergic contact dermatitis was reported; [Kanerva, p. 783] Aminotriazole may be hepatotoxic on ingestion. [Zimmerman, p. 393] The following herbicides have an oral LD50 of >1 gm/kg and have little or no acute toxicity in humans: Alachlor, Amitrole, Ammonium sulfamate, Atrazine, Dalapon, Dicamba, Glyphosphate, Monuron, Oryzalin, Picloram, Propanil, Simazine, etc. [LaDou, p. 613] TLV basis: thyroid effects; [ACGIH]
Kanerva - Rustemeyer L, Elsner P, John SM, Maibach HI (eds). Kanerva's Occupational Dermatology, 2nd Ed. Berlin: Springer-Verlag, 2012., p. 783
Zimmerman - Zimmerman HJ. Hepatotoxicity. Philadelphia: Lippincott Williams & Wilkins, 1999., p. 393
LaDou - LaDou J, Harrison R (eds). Current Occupational & Environmental Medicine, 5th Ed. New York: McGraw-Hill, 2014., p. 613
ACGIH - Documentation of the TLVs and BEIs, 7th Ed. Cincinnati: ACGIH Worldwide, 2020.
The major hazards encountered in the use and handling of 2-amino-1,3,4-triazole stem from its toxicologic properties. Exposure to this odorless, colorless-to-white, crystalline substance may occur from its manufacture, handling, and use as a weed-killer. Effects from exposure may include dermal irritation, muscle spasms, shortness-of-breath, and anorexia. Also, the International Agency for Research on Cancer (IARC) has designated this substance as a Group 3 carcinogen, meaning, "The agent is not classifiable as to its carcinogenicity to humans." OSHA has set a Time Weighted Average (TWA) limit of 0.2 mg/cu m as a final rule to become effective December 31, 1992. In activities and situations where over-exposure may occur, wear a protective suit and a carefully fitted respirator. If contact should occur, irrigate exposed eyes with copious amounts of tepid water for at least 15 minutes, and wash exposed skin thoroughly with soap and water. Smoking, drinking, and eating should be prohibited in 2-amino-1,3,4-tiazole work areas, and cleanliness following the handling of this substance should be emphasized. While considered nonflammable, 2-amino-1,3,4-triazole will emit highly toxic fumes when strongly heated. 2-Amino-1,3,4-triazole should be kept in securely sealed containers, away from light (which will act to decompose the substance). Choice of container should take into consideration that 2-amino-1,3,4-triazole is mildly corrosive to iron, aluminum, copper, and copper alloys.

12.1.7 Fire Potential

Aqueous, nonflammable, as amitrol-t; dry powder, non-flammable, as amizol.
Weed Science Society of America. Herbicide Handbook. 5th ed. Champaign, Illinois: Weed Science Society of America, 1983., p. 20

12.1.8 Skin, Eye, and Respiratory Irritations

Potential symptoms of overexposure are irritation of eyes, skin... .
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. 13th Edition, Whitehouse Station, NJ: Merck and Co., Inc., 2001., p. 86

12.1.9 EPA Hazardous Waste Number

U011; A toxic waste when a discarded commercial chemical product or manufacturing chemical intermediate or an off-specification commercial chemical product or manufacturing chemical intermediate.

12.2 Safety and Hazard Properties

12.2.1 Flammable Limits

Flammability
Noncombustible Solid, but may be dissolved in flammable liquids.

12.2.2 Physical Dangers

Dust explosion possible if in powder or granular form, mixed with air.

12.2.3 OSHA Standards

Vacated 1989 OSHA PEL TWA 0.2 mg/cu m is still enforced in some states.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997., p. 359

12.2.4 NIOSH Recommendations

NIOSH considers amitrole to be a potential occupational carcinogen.
NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)
NIOSH usually recommends that occupational exposures to carcinogens be limited to the lowest feasible concn.
NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)
Recommended Exposure Limit: 10 Hr Time-Weighted Avg: 0.2 mg/cu m.
NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)

12.3 First Aid Measures

Inhalation First Aid
Fresh air, rest.
Skin First Aid
Remove contaminated clothes. Rinse skin with plenty of water or shower.
Eye First Aid
First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.
Ingestion First Aid
Rinse mouth. Refer for medical attention .

12.3.1 First Aid

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. IMMEDIATELY call a hospital or poison control center even if no symptoms (such as redness or irritation) develop. IMMEDIATELY transport the victim to a hospital for treatment after washing the affected areas.

INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. IMMEDIATELY call a physician and be prepared to transport the victim to a hospital even if no symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing.

INGESTION: DO NOT INDUCE VOMITING. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. Be prepared to transport the victim to a hospital if advised by a physician. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. IMMEDIATELY transport the victim to a hospital.

OTHER: Since this chemical is a known or suspected carcinogen you should contact a physician for advice regarding the possible long term health effects and potential recommendation for medical monitoring. Recommendations from the physician will depend upon the specific compound, its chemical, physical and toxicity properties, the exposure level, length of exposure, and the route of exposure. (NTP, 1992)

National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.

(See general first aid procedures)

Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.

Skin: Water wash immediately - If this chemical contacts the skin, immediately wash the contaminated skin with water. If this chemical penetrates the clothing, immediately remove the clothing and wash the skin with water. If symptoms occur after washing, get medical attention immediately.

Breathing: Respiratory support

Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately.

12.4 Fire Fighting

Fires involving this chemical can be controlled with a dry chemical, carbon dioxide or Halon extinguisher. A water spray may also be used. (NTP, 1992)
National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
Use water spray, foam, powder, carbon dioxide.

12.5 Accidental Release Measures

12.5.1 Isolation and Evacuation

Excerpt from ERG Guide 171 [Substances (Low to Moderate Hazard)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

12.5.2 Spillage Disposal

Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Do NOT let this chemical enter the environment. Sweep spilled substance into covered sealable, plastic containers. If appropriate, moisten first to prevent dusting. Carefully collect remainder. Then store and dispose of according to local regulations.

12.5.3 Cleanup Methods

PRECAUTIONS FOR "CARCINOGENS": A high-efficiency particulate arrestor (HEPA) or charcoal filters can be used to minimize amt of carcinogen in exhausted air ventilated safety cabinets, lab hoods, glove boxes or animal rooms ... Filter housing that is designed so that used filters can be transferred into plastic bag without contaminating maintenance staff is avail commercially. Filters should be placed in plastic bags immediately after removal ... . The plastic bag should be sealed immediately ... . The sealed bag should be labelled properly ... . Waste liquids ... should be placed or collected in proper containers for disposal. The lid should be secured & the bottles properly labelled. Once filled, bottles should be placed in plastic bags, so that outer surface ... is not contaminated ... . The plastic bag should also be sealed & labelled. ... Broken glassware ... should be decontaminated by solvent extraction, by chemical destruction, or in specially designed incinerators. /Chemical Carcinogens/
Montesano, R., H. Bartsch, E.Boyland, G. Della Porta, L. Fishbein, R. A. Griesemer, A.B. Swan, L. Tomatis, and W. Davis (eds.). Handling Chemical Carcinogens in the Laboratory: Problems of Safety. IARC Scientific Publications No. 33. Lyon, France: International Agency for Research on Cancer, 1979., p. 15
If a spill occurs, clean it up promptly. Don't wash it away. Instead, sprinkle the spill with sawdust, vermiculite, or kitty litter. Sweep it into a plastic garbage bag, and dispose of it as directed on the pesticide product label.
USEPA/Prevention, Pesticides, and Toxic Substances; Citizen's Guide to Pest Control and Pesticide Safety p.20 (Septemper 1995) EPA 730-K-95-001
After Applying a Pesticide, Indoors or Outdoors. To remove pesticide residues, use a bucket to rinse tools or equipment three times, including any containers or utensils that you used when mixing the pesticide. Then pour the rinsewater into the pesticide sprayer and reuse the solution by applying it according to the pesticide product label directions. After applying any pesticide wash your hands and any other parts of your body that may have come in contact with the pesticide..To prevent tracking pesticides inside, remove or rinse your boots or shoes before entering your home. Wash any clothes that have been exposed to a lot of pesticide separately from your regular wash.
USEPA/Prevention, Pesticides, and Toxic Substances; Citizen's Guide to Pest Control and Pesticide Safety p.22 (Septemper 1995) EPA 730-K-95-001

12.5.4 Disposal Methods

[40 CFR 240-280, 300-306, 702-799 (7/1/2005)] Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number U011, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.
Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number U011, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.
40 CFR 240-280, 300-306, 702-799 (7/1/89)
A potential candidate for rotary kiln incineration at a temperature range of 820 to 1,600 °C and residence times of seconds for liquids and gases, and hours for solids. A potential candidate for fluidized bed incineration at a temperature range of 450 to 980 °C and residence times of seconds for liquids and gases, and longer for solids.
USEPA; Engineering Handbook for Hazardous Waste Incineration p.3-11 (1981) EPA 68-03-3025
The following wastewater treatment technologies have been investigated for aminotriazole: Concentraction process: Biological treatment.
USEPA; Management of Hazardous Waste Leachate, EPA Contract No.68-03-2766 p.E-55 (1982)
For more Disposal Methods (Complete) data for AMITROLE (11 total), please visit the HSDB record page.

12.5.5 Preventive Measures

PRECAUTIONS FOR "CARCINOGENS": Smoking, drinking, eating, storage of food or of food & beverage containers or utensils, & the application of cosmetics should be prohibited in any laboratory. All personnel should remove gloves, if worn, after completion of procedures in which carcinogens have been used. They should ... wash ... hands, preferably using dispensers of liq detergent, & rinse ... thoroughly. Consideration should be given to appropriate methods for cleaning the skin, depending on nature of the contaminant. No standard procedure can be recommended, but the use of organic solvents should be avoided. Safety pipettes should be used for all pipetting. /Chemical Carcinogens/
Montesano, R., H. Bartsch, E.Boyland, G. Della Porta, L. Fishbein, R. A. Griesemer, A.B. Swan, L. Tomatis, and W. Davis (eds.). Handling Chemical Carcinogens in the Laboratory: Problems of Safety. IARC Scientific Publications No. 33. Lyon, France: International Agency for Research on Cancer, 1979., p. 8
PRECAUTIONS FOR "CARCINOGENS": In animal laboratory, personnel should remove their outdoor clothes & wear protective suits (preferably disposable, one-piece & close-fitting at ankles & wrists), gloves, hair covering & overshoes. ... clothing should be changed daily but ... discarded immediately if obvious contamination occurs ... /also,/ workers should shower immediately. In chemical laboratory, gloves & gowns should always be worn ... however, gloves should not be assumed to provide full protection. Carefully fitted masks or respirators may be necessary when working with particulates or gases, & disposable plastic aprons might provide addnl protection. If gowns are of distinctive color, this is a reminder that they should not be worn outside of lab. /Chemical Carcinogens/
Montesano, R., H. Bartsch, E.Boyland, G. Della Porta, L. Fishbein, R. A. Griesemer, A.B. Swan, L. Tomatis, and W. Davis (eds.). Handling Chemical Carcinogens in the Laboratory: Problems of Safety. IARC Scientific Publications No. 33. Lyon, France: International Agency for Research on Cancer, 1979., p. 8
PRECAUTIONS FOR "CARCINOGENS": ... Operations connected with synth & purification ... should be carried out under well-ventilated hood. Analytical procedures ... should be carried out with care & vapors evolved during ... procedures should be removed. ... Expert advice should be obtained before existing fume cupboards are used ... & when new fume cupboards are installed. It is desirable that there be means for decreasing the rate of air extraction, so that carcinogenic powders can be handled without ... powder being blown around the hood. Glove boxes should be kept under negative air pressure. Air changes should be adequate, so that concn of vapors of volatile carcinogens will not occur. /Chemical Carcinogens/
Montesano, R., H. Bartsch, E.Boyland, G. Della Porta, L. Fishbein, R. A. Griesemer, A.B. Swan, L. Tomatis, and W. Davis (eds.). Handling Chemical Carcinogens in the Laboratory: Problems of Safety. IARC Scientific Publications No. 33. Lyon, France: International Agency for Research on Cancer, 1979., p. 8
PRECAUTIONS FOR "CARCINOGENS": Vertical laminar-flow biological safety cabinets may be used for containment of in vitro procedures ... provided that the exhaust air flow is sufficient to provide an inward air flow at the face opening of the cabinet, & contaminated air plenums that are under positive pressure are leak-tight. Horizontal laminar-flow hoods or safety cabinets, where filtered air is blown across the working area towards the operator, should never be used ... Each cabinet or fume cupboard to be used ... should be tested before work is begun (eg, with fume bomb) & label fixed to it, giving date of test & avg air-flow measured. This test should be repeated periodically & after any structural changes. /Chemical Carcinogens/
Montesano, R., H. Bartsch, E.Boyland, G. Della Porta, L. Fishbein, R. A. Griesemer, A.B. Swan, L. Tomatis, and W. Davis (eds.). Handling Chemical Carcinogens in the Laboratory: Problems of Safety. IARC Scientific Publications No. 33. Lyon, France: International Agency for Research on Cancer, 1979., p. 9
For more Preventive Measures (Complete) data for AMITROLE (18 total), please visit the HSDB record page.

12.6 Handling and Storage

12.6.1 Nonfire Spill Response

SMALL SPILLS AND LEAKAGE: If you spill this chemical, you should dampen the solid spill material with water, then transfer the dampened material to a suitable container. Use absorbent paper dampened with water to pick up any remaining material. Seal your contaminated clothing and the absorbent paper in a vapor-tight plastic bag for eventual disposal. Wash all contaminated surfaces with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.

STORAGE PRECAUTIONS: You should keep this material in a tightly closed container under an inert atmosphere, and store it at refrigerated temperatures. (NTP, 1992)

National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.

12.6.2 Safe Storage

Store in an area without drain or sewer access. Separated from strong acids, strong oxidants, acid anhydrides and acid chlorides. Do NOT store or transport in containers made from iron, aluminium or copper and its alloys. Separated from food and feedstuffs.

12.6.3 Storage Conditions

Store at room temperature
Crop Protection Handbook 2005. (Formerly Farm and Chemicals Handbook) Willoughby, OH: Meister Publishing Co., 2005., p. D-20
PRECAUTIONS FOR "CARCINOGENS": Storage site should be as close as practical to lab in which carcinogens are to be used, so that only small quantities required for ... expt need to be carried. Carcinogens should be kept in only one section of cupboard, an explosion-proof refrigerator or freezer (depending on chemicophysical properties ...) that bears appropriate label. An inventory ... should be kept, showing quantity of carcinogen & date it was acquired ... . Facilities for dispensing ... should be contiguous to storage area. /Chemical Carcinogens/
Montesano, R., H. Bartsch, E.Boyland, G. Della Porta, L. Fishbein, R. A. Griesemer, A.B. Swan, L. Tomatis, and W. Davis (eds.). Handling Chemical Carcinogens in the Laboratory: Problems of Safety. IARC Scientific Publications No. 33. Lyon, France: International Agency for Research on Cancer, 1979., p. 13
Safe Storage of Pesticides. Always store pesticides in their original containers, complete with labels that list ingredients, directions for use, and first aid steps in case of accidental poisoning. Never store pesticides in cabinets with or near food, animal feed, or medical supplies. Do not store pesticides in places where flooding is possible or in places where they might spill or leak into wells, drains, ground water, or surface water.
USEPA/Prevention, Pesticides, and Toxic Substances; Citizen's Guide to Pest Control and Pesticide Safety p.23 (Septemper 1995) EPA 730-K-95-001

12.7 Exposure Control and Personal Protection

Maximum Allowable Concentration (MAK)
0.2 [mg/m3], inhalable fraction[German Research Foundation (DFG)]

12.7.2 Permissible Exposure Limit (PEL)

12.7.3 Immediately Dangerous to Life or Health (IDLH)

A potential occupational carcinogen. (NIOSH, 2024)
NIOSH considers amitrole to be a potential occupational carcinogen.
NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)

Ca [N.D.]

See: IDLH INDEX

12.7.4 Threshold Limit Values (TLV)

0.2 [mg/m3]
8 hr Time Weighted Avg (TWA): 0.2 mg/cu m.
American Conference of Governmental Industrial Hygienists TLVs and BEIs. Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. Cincinnati, OH, 2008, p. 11
Excursion Limit Recommendation: Excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a work day, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded.
American Conference of Governmental Industrial Hygienists TLVs and BEIs. Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. Cincinnati, OH, 2008, p. 5
A3; Confirmed animal carcinogen with unknown relevance to humans.
American Conference of Governmental Industrial Hygienists TLVs and BEIs. Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. Cincinnati, OH, 2008, p. 11
0.2 mg/m
TLV-TWA (Time Weighted Average)
0.2 mg/m³ [1983]

12.7.5 Occupational Exposure Limits (OEL)

EU-OEL
0.2 mg/m
MAK (Maximale Arbeitsplatz Konzentration)
(inhalable fraction): 0.2 mg/m

12.7.6 Other Standards Regulations and Guidelines

West Germany: 0.2 mg/cu m
American Conference of Governmental Industrial Hygienists. Documentation of the Threshold Limit Values and Biological Exposure Indices. 5th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, 1986., p. 25

12.7.7 Inhalation Risk

A nuisance-causing concentration of airborne particles can be reached on spraying.

12.7.8 Effects of Short Term Exposure

The substance is mildly irritating to the eyes and skin.

12.7.9 Effects of Long Term Exposure

Tumours have been detected in experimental animals but may not be relevant to humans.

12.7.10 Personal Protective Equipment (PPE)

Excerpt from NIOSH Pocket Guide for Amitrole:

Skin: PREVENT SKIN CONTACT - Wear appropriate personal protective clothing to prevent skin contact.

Eyes: PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact.

Wash skin: DAILY - The worker should wash daily at the end of each work shift, and prior to eating, drinking, smoking, etc.

Remove: WHEN WET OR CONTAMINATED - Work clothing that becomes wet or significantly contaminated should be removed and replaced.

Change: DAILY - Workers whose clothing may have become contaminated should change into uncontaminated clothing before leaving the work premises.

Provide:

• EYEWASH - Eyewash fountains should be provided in areas where there is any possibility that workers could be exposed to the substances; this is irrespective of the recommendation involving the wearing of eye protection.

• QUICK DRENCH - Facilities for quickly drenching the body should be provided within the immediate work area for emergency use where there is a possibility of exposure. [Note: It is intended that these facilities provide a sufficient quantity or flow of water to quickly remove the substance from any body areas likely to be exposed. The actual determination of what constitutes an adequate quick drench facility depends on the specific circumstances. In certain instances, a deluge shower should be readily available, whereas in others, the availability of water from a sink or hose could be considered adequate.] (NIOSH, 2024)

PRECAUTIONS FOR "CARCINOGENS": ... Dispensers of liq detergent /should be available./ ... Safety pipettes should be used for all pipetting. ... In animal laboratory, personnel should ... wear protective suits (preferably disposable, one-piece & close-fitting at ankles & wrists), gloves, hair covering & overshoes. ... In chemical laboratory, gloves & gowns should always be worn ... however, gloves should not be assumed to provide full protection. Carefully fitted masks or respirators may be necessary when working with particulates or gases, & disposable plastic aprons might provide addnl protection. ... Gowns ... /should be/ of distinctive color, this is a reminder that they are not to be worn outside the laboratory. /Chemical Carcinogens/
Montesano, R., H. Bartsch, E.Boyland, G. Della Porta, L. Fishbein, R. A. Griesemer, A.B. Swan, L. Tomatis, and W. Davis (eds.). Handling Chemical Carcinogens in the Laboratory: Problems of Safety. IARC Scientific Publications No. 33. Lyon, France: International Agency for Research on Cancer, 1979., p. 8
Wear appropriate personal protective clothing to prevent skin contact.
NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)
Wear appropriate eye protection to prevent eye contact.
NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)
Eyewash fountains should be provided in areas where there is any possibility that workers could be exposed to the substance; this is irrespective of the recommendation involving the wearing of eye protection.
NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)
For more Personal Protective Equipment (PPE) (Complete) data for AMITROLE (8 total), please visit the HSDB record page.

(See personal protection and sanitation codes)

Skin: Prevent skin contact - Wear appropriate personal protective clothing to prevent skin contact.

Eyes: Prevent eye contact - Wear appropriate eye protection to prevent eye contact.

Wash skin: Daily - The worker should wash daily at the end of each work shift, and prior to eating, drinking, smoking, etc.

Remove: When wet or contaminated

Change: Daily - Workers whose clothing may have become contaminated should change into uncontaminated clothing before leaving the work premises.

Provide: Eyewash, Quick drench

12.7.11 Respirator Recommendations

NIOSH

At concentrations above the NIOSH REL, or where there is no REL, at any detectable concentration:

(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode

(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus

Escape:

(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister having an N100, R100, or P100 filter.

Click here for information on selection of N, R, or P filters.

Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

12.7.12 Preventions

Fire Prevention
NO open flames.
Exposure Prevention
STRICT HYGIENE!
Inhalation Prevention
Avoid inhalation of dust and aerosol.
Skin Prevention
Protective gloves. Protective clothing.
Eye Prevention
Wear face shield or eye protection in combination with breathing protection if powder.
Ingestion Prevention
Do not eat, drink, or smoke during work.

12.8 Stability and Reactivity

12.8.1 Air and Water Reactions

Water soluble. Aqueous solutions are neutral. Dust may form an explosive mixture in air.

12.8.2 Reactive Group

Azo, Diazo, Azido, Hydrazine, and Azide Compounds

Amines, Aromatic

12.8.3 Reactivity Profile

AMITROLE is a triazole derivative. The triazoles are a group that contain several derivatives that are highly explosive materials. They are sensitive to heat, friction, and impact. Sensitivity varies with the type substitution to the triazole ring. Metal chelated and halogen substitution of the triazole ring make for a particularly heat sensitive material. Azido and nitro derivatives have been employed as high explosives. No matter the derivative these materials should be treated as explosives. AMITROLE forms chelates with some metals. It is corrosive to iron, copper and aluminum. Forms salts with most acids and alkalis. This compound is incompatible with strong oxidizers, strong acids, acid chlorides and acid anhydrides (NTP, 1992).
National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.

12.8.4 Hazardous Reactivities and Incompatibilities

Light (decomposes), strong oxidizers [Note: Corrosive to iron, aluminum & copper].
NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases CD-ROM. Department of Health & Human Services, Centers for Disease Prevention & Control. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2005-151 (2005)

12.9 Transport Information

12.9.1 Shipment Methods and Regulations

PRECAUTIONS FOR "CARCINOGENS": Procurement ... of unduly large amt ... should be avoided. To avoid spilling, carcinogens should be transported in securely sealed glass bottles or ampoules, which should themselves be placed inside strong screw-cap or snap-top container that will not open when dropped & will resist attack from the carcinogen. Both bottle & the outside container should be appropriately labelled. ... National post offices, railway companies, road haulage companies & airlines have regulations governing transport of hazardous materials. These authorities should be consulted before ... material is shipped. /Chemical Carcinogens/
Montesano, R., H. Bartsch, E.Boyland, G. Della Porta, L. Fishbein, R. A. Griesemer, A.B. Swan, L. Tomatis, and W. Davis (eds.). Handling Chemical Carcinogens in the Laboratory: Problems of Safety. IARC Scientific Publications No. 33. Lyon, France: International Agency for Research on Cancer, 1979., p. 13
PRECAUTIONS FOR "CARCINOGENS": When no regulations exist, the following procedure must be adopted. The carcinogen should be enclosed in a securely sealed, watertight container (primary container), which should be enclosed in a second, unbreakable, leakproof container that will withstand chem attack from the carcinogen (secondary container). The space between primary & secondary container should be filled with absorbent material, which would withstand chem attack from the carcinogen & is sufficient to absorb the entire contents of the primary container in the event of breakage or leakage. Each secondary container should then be enclosed in a strong outer box. The space between the secondary container & the outer box should be filled with an appropriate quantity of shock-absorbent material. Sender should use fastest & most secure form of transport & notify recipient of its departure. If parcel is not received when expected, carrier should be informed so that immediate effort can be made to find it. Traffic schedules should be consulted to avoid ... arrival on weekend or holiday ... /Chemical Carcinogens/
Montesano, R., H. Bartsch, E.Boyland, G. Della Porta, L. Fishbein, R. A. Griesemer, A.B. Swan, L. Tomatis, and W. Davis (eds.). Handling Chemical Carcinogens in the Laboratory: Problems of Safety. IARC Scientific Publications No. 33. Lyon, France: International Agency for Research on Cancer, 1979., p. 13

12.9.2 DOT Label

Class 9

12.9.3 Packaging and Labelling

Do not transport with food and feedstuffs.

12.9.4 EC Classification

Symbol: Xn, N; R: 48/22-63-51/53; S: (2)-13-36/37-61

12.9.5 UN Classification

UN Hazard Class: 9; UN Pack Group: III

12.10 Regulatory Information

The Australian Inventory of Industrial Chemicals
Chemical: 1H-1,2,4-Triazol-3-amine
California Safe Cosmetics Program (CSCP) Reportable Ingredient

Hazard Traits - Carcinogenicity

Authoritative List - NTP RoC - reasonable; Prop 65

Report - regardless of intended function of ingredient in the product

Status Regulation (EC)
01/21/EC, 2010/77/EU, Reg (EU) 2015/408, Reg. (EU) 2015/1885, Reg. (EU) 2016/871, Reg. (EU) No 540/2011
REACH Registered Substance
New Zealand EPA Inventory of Chemical Status
Amitrole: HSNO Approval: HSR002898 Approved with controls

12.10.1 CERCLA Reportable Quantities

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 10 lb or 4.54 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b).
40 CFR 302.4; U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of February 6, 2006: https://www.ecfr.gov

12.10.2 TSCA Requirements

Section 8(a) of TSCA requires manufacturers of this chemical substance to report preliminary assessment information concerned with production, exposure, and use to EPA as cited in the preamble in 51 FR 41329.
40 CFR 712.30; U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of February 6, 2006: https://www.ecfr.gov
Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. Amitrole is included on this list.
40 CFR 716.120; U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of February 6, 2006: https://www.ecfr.gov

12.10.3 RCRA Requirements

U011; As stipulated in 40 CFR 261.33, when amitrole, as a commercial chemical product or manufacturing chemical intermediate or an off-specification commercial chemical product or a manufacturing chemical intermediate, becomes a waste, it must be managed according to Federal and/or State hazardous waste regulations. Also defined as a hazardous waste is any residue, contaminated soil, water, or other debris resulting from the cleanup of a spill, into water or on dry land, of this waste. Generators of small quantities of this waste may qualify for partial exclusion from hazardous waste regulations (40 CFR 261.5).
40 CFR 261.33; U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of February 6, 2006: https://www.ecfr.gov

12.10.4 FIFRA Requirements

Section 4(g)(2)(A) of FIFRA calls for the Agency to determine, after submission of relevant data concerning an active ingredient, whether products containing the active ingredients are eligible for reregistration. The Agency has previously identified and required the submission of the generic (i.e. active ingredient specific) data required to support reregistration of products containing Amitrole active ingredients. The Agency has completed its review of these generic data, and has determined that the data are sufficient to support reregistration of all products containing Amitrole.
USEPA/Office of Pesticide Programs; Reregistration Eligibility Decision Document - Amitrole. Available from, as of February 7, 2006: https://www.epa.gov/pesticides/reregistration/status.htm
As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their future use. Under this pesticide reregistration program, EPA examines health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether they are eligible for reregistration. In addition, all pesticides must meet the new safety standard of the Food Quality Protection Act of 1996. 2-Amino-1,3,4-triazole is found on List A, which contains most food use pesticides and consists of the 194 chemical cases (or 350 individual active ingredients) for which EPA issued registration standards prior to FIFRA '88. Case No: 0095; Pesticide type: herbicide; Registration Standard Date: 03/30/84; Case Status: RED Approved 09/96; OPP has made a decision that some/all uses of the pesticide are eligible for reregistration, as reflected in a Reregistration Eligibility Decision (RED) document .; Active ingredient (AI): 2-amino-1,3,4-triazole; Data Call-in (DCI) Date(s): 08/16/91, 12/24/96; AI Status: OPP has completed a Reregistration Eligibility Decision (RED) for the case/AI.
United States Environmental Protection Agency/ Prevention, Pesticides and Toxic Substances; Status of Pesticides in Registration, Reregistration, and Special Review. (1998) EPA 738-R-98-002, p. 85

12.11 Other Safety Information

12.11.1 Special Reports

AMITROLE; WHO TECH REP SER (574): 3-49 (1975). REVIEW OF AMITROLE
National Toxicology Program. Eleventh Report on Carcinogens (2005). The Report on Carcinogens is an informational scientific and public health document that identifies and discusses substances (including agents, mixtures, or exposure circumstances) that may pose a carcinogenic hazard to human health. Amitrole (61-82-5) is listed as reasonably anticipated to be a human carcinogen.[Available from, as of July 31, 2009: http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s013amit.pdf]
USEPA/Office of Pesticide Programs; Reregistration Eligibility Decision Document - Amitrole. The RED summarizes the risk assessment conclusions and outlines any risk reduction measures necessary for the pesticide to continue to be registered in the U.S.[Available from, as of February 7, 2006: http://www.epa.gov/pesticides/reregistration/status.htm]
WHO; Environ Health Criteria 158: 2-Amino-1,3,4-Triazole (1994)

13 Toxicity

13.1 Toxicological Information

13.1.1 RAIS Toxicity Values

Inhalation Unit Risk (IUR) (ug/m^3)^-1
0.00027
Inhalation Unit Risk Reference
CALEPA
Oral Slope Factor (CSFo)(mg/kg-day)^-1
0.94
Oral Slope Factor Reference
CALEPA

13.1.2 NIOSH Toxicity Data

13.1.3 Evidence for Carcinogenicity

Cancer Classification: Group B2 Probable Human Carcinogen
USEPA Office of Pesticide Programs, Health Effects Division, Science Information Management Branch: "Chemicals Evaluated for Carcinogenic Potential" (April 2006)
The Human Health Assessment Group in EPA's Office of Health and Environmental Assessment has evaluated amitrole for carcinogenicity. According to their analysis, the weight-of-evidence for amitrole is group B2, which is based on inadequate evidence in humans and sufficient evidence in animals. As a group B2 chemical, amitrole is considered a probable human carcinogen.
USEPA; Methodology for Evaluating Potential Carcinogenicity in Support of Reportable Quantity Adjustments Pursuant to Cercla Section 102 (Final) p.37 (1988) EPA/600/8-89/053
Evaluation: There is inadequate evidence in humans for the carcinogenicity of amitrole. There is sufficient evidence in experimental animals for the carcinogenicity of amitrole. Overall evaluation: Amitrole is not classifiable as to its carcinogenicity to humans (Group 3). In making its evaluation, the Working Group concluded that amitrole produces thyroid tumors in mice and rats by a non-genotoxic mechanism, which involves interference with the functioning of the thyroid peroxidase, resulting in a reduction in circulating thyroid hormone concn and incr secretion of thyroid stimulating hormone. Consequently, amitrole would not be expected to produce thyroid cancer in humans exposed to concn that do not alter thyroid hormone homeostasis. An additional consideration of the Working Group, based on lack of genotoxicity of amitrole, was that the liver tumors in mice and benign tumors in rats were also produced by a non-genotoxic mechanism. Evidence from epidemiological studies and from toxicological studies in experimental animals provide compelling evidence that rodents are substantially more sensitive than humans to the development of thyroid tumors in response to thyroid hormone imbalance.
IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V79 403 (2001)
A3; Confirmed animal carcinogen with unknown relevance to humans.
American Conference of Governmental Industrial Hygienists TLVs and BEIs. Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. Cincinnati, OH 2010, p. 11
Amitrole: reasonably anticipated to be a human carcinogen.
DHHS/National Toxicology Program; Eleventh Report on Carcinogens: Amitrole (61-82-5) (January 2005). Available from, as of July 31, 2009: https://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s013amit.pdf

13.1.4 Carcinogen Classification

IARC Carcinogenic Agent
Amitrole
IARC Carcinogenic Classes
Group 3: Not classifiable as to its carcinogenicity to humans
IARC Monographs

Volume 79: (2001) Some Thyrotropic Agents

Volume Sup 7: Overall Evaluations of Carcinogenicity: An Updating of IARC Monographs Volumes 1 to 42, 1987; 440 pages; ISBN 92-832-1411-0 (out of print)

Additional information
NB Overall evaluation downgraded to Group 3 with supporting evidence from other relevant data

13.1.5 Exposure Routes

The substance can be absorbed into the body by inhalation of its aerosol.
inhalation, ingestion, skin and/or eye contact

13.1.6 Symptoms

Skin Exposure
Redness.
Eye Exposure
Redness. Pain.
irritation eyes, skin; dyspnea (breathing difficulty), muscle spasms, ataxia, anorexia, salivation, increased body temperature; lassitude (weakness, exhaustion), skin dryness, depression (thyroid function suppression)

13.1.7 Target Organs

Eyes, skin, thyroid

13.1.8 Cancer Sites

[in animals: liver, thyroid &amp; pituitary gland tumors]

13.1.10 Adverse Effects

Occupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation.

Reproductive Toxin - A chemical that is toxic to the reproductive system, including defects in the progeny and injury to male or female reproductive function. Reproductive toxicity includes developmental effects. See Guidelines for Reproductive Toxicity Risk Assessment.

Skin Sensitizer - An agent that can induce an allergic reaction in the skin.

NTP Carcinogen - Reasonably anticipated to be a human carcinogen.

ACGIH Carcinogen - Confirmed Animal.

13.1.11 Acute Effects

13.1.12 Toxicity Data

LC50 >500 mg/m3

13.1.13 Interactions

... Effects on rat of 2 inhibitors ... on oxidation of methanol & ethanol to carbon dioxide, & on activities in vitro of rat-liver alcohol dehydrogenase & catalase. ... 3-amino-1,2,4-triazole considerably decreased ... carbon dioxide production from methanol ... & marginally ... from ethanol. ... There was additive effect ... when /used simultaneously with/ pyrazole ... .
The Chemical Society. Foreign Compound Metabolism in Mammals Volume 3. London: The Chemical Society, 1975., p. 624
3-amino-1,2,4-triazole administration (AT) at 3 and 6 hr led to the formation of round small vesicles from the rough endoplasmic reticulum, detachment of ribosomes, appearance of extensive areas of smooth endoplasmic reticulum, appearance of elongated and distorted mitochondria with an increase in the number of peroxisomes. The administration of carbon tetrachloride to AT-pretreated animals led to a mutual cancellation of the effects on the reticulum, & formation of myelin figures was prevented.
BERNACCHI AS ET AL; BR J EXP PATHOL 63 (1): 35-42 (1982)
The placental transport of mercury in pregnant mice and its localization in the embryo and fetus from early organogenesis through the whole fetal period was studied by whole-body autoradiography and gamma counting. Preadmission to the dams of aminotriazole resulted in higher fetal concentration (esp in the liver) of mercury after inhalation of mercuric oxide but not after injection of (2+)mercury ion.
KHAYAT A, DENCKER L; INT J BIOL RES PREGNANCY 3 (1): 38-46 (1982)
Inhalation of radioactive metallic mercury vapor in the mouse resulted in an accumulation of mercury in several organs where no specific uptake was observed after iv injection of inorganic mercury. Ethanol and aminotriazole (catalase inhibitors) decreased the concentration in several of these organs, although not in an exactly similar pattern. In the livers of non-treated animals most of the inhaled mercury accumulated in the hepatocytes in the periphery of the lobuli (periportal region), close to where the blood vessels enter the liver parenchyma. Treatment with aminotriazole increased the liver mercury content, with more or less all the hepatocytes apparently engaged in the oxidation of mercuric oxide.
Khayata A, Dencker L; J Appl Toxicol 3 (2): 66-74 (1983)
For more Interactions (Complete) data for AMITROLE (9 total), please visit the HSDB record page.

13.1.14 Antidote and Emergency Treatment

Basic treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poison A and B/
Bronstein, A.C., P.L. Currance; Emergency Care for Hazardous Materials Exposure. 2nd ed. St. Louis, MO. Mosby Lifeline. 1994., p. 139
Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in respiratory arrest. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start an IV with D5W /SRP: "To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. Consider drug therapy for pulmonary edema ... . For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poison A and B/
Bronstein, A.C., P.L. Currance; Emergency Care for Hazardous Materials Exposure. 2nd ed. St. Louis, MO. Mosby Lifeline. 1994., p. 139

13.1.15 Medical Surveillance

PRECAUTIONS FOR "CARCINOGENS": Whenever medical surveillance is indicated, in particular when exposure to a carcinogen has occurred, ad hoc decisions should be taken concerning ... /cytogenetic and/or other/ tests that might become useful or mandatory. /Chemical Carcinogens/
Montesano, R., H. Bartsch, E.Boyland, G. Della Porta, L. Fishbein, R. A. Griesemer, A.B. Swan, L. Tomatis, and W. Davis (eds.). Handling Chemical Carcinogens in the Laboratory: Problems of Safety. IARC Scientific Publications No. 33. Lyon, France: International Agency for Research on Cancer, 1979., p. 23

13.1.16 Human Toxicity Excerpts

/HUMAN EXPOSURE STUDIES/ A single oral dose of 100 mg amitrole inhibited the 131I-uptake by the thyroid for 24 hours in healthy persons and persons with hyperthyroidism. 10 mg amitrole had only a very slight effect and has to be seen as a threshold dose.
American Conference of Governmental Industrial Hygienists. Documentation of the TLV's and BEI's with Other World Wide Occupational Exposure Values. CD-ROM Cincinnati, OH 45240-1634 2005., p. 2
/HUMAN EXPOSURE STUDIES/ Intentional ingestion of a commercial mixture of amitrole and diuron at a dose equivalent to 20 mg/kg bw of amitrole was reported to have caused no symptoms of poisoning in a woman
IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work). Available at: https://monographs.iarc.fr/ENG/Classification/index.php, p. V79 392(2001)
/HUMAN EXPOSURE STUDIES/ During a patch test conducted with human volunteers, amitrole exerted no primary dermal irritant effect after an exposure period of 4-8 hr; a slight irritant effect was observed in three out of six volunteers after 24 hr.
WHO; Environmental Health Criteria Document No. 158: Amitrole (61-82-5). Available from, as of January 30, 2006: https://www.inchem.org/pages/ehc.html
/HUMAN EXPOSURE STUDIES/ ...A study conducted on five men involved in spraying amitrole over a period of 10 working days on utility rights-of-way in West Virginia. The amitrole (at a concentration of approximately 500 g of active ingredient per 100 liters of water), was applied using handheld hydraulic spray guns. Medical monitoring, particularly of the thyroid, was carried out both pre- and post-spraying. Thyroid gland palpation and neck measurements were undertaken 19 days prior to exposure and 14 days after the last exposure. Thyroid function tests were performed at 19, 11 and 4 days pre-exposure and 0, 7 and 14 days after the last exposure. All subjects were within the normal range for thyroid function and no differences were found in any comparisons of thyroid function. It was estimated that dermal exposure over the 10-day period was approximately 340 mg per day for each man.
WHO; Environmental Health Criteria Document No. 158: Amitrole (61-82-5). Available from, as of January 30, 2006: https://www.inchem.org/pages/ehc.html
For more Human Toxicity Excerpts (Complete) data for AMITROLE (10 total), please visit the HSDB record page.

13.1.17 Non-Human Toxicity Excerpts

/LABORATORY ANIMALS: Acute Exposure/ 3-Aminotriazole is known to reduce catalase levels in ocular tissues when given iv or orally. Rabbits were given either 4 mL/kg of a 3 M solution of 3-aminotriazole iv or a 2% solution as drinking fluid. Intravenous 3-aminotriazole administration was followed at 4 hr by an intracameral injection of hydrogen peroxide to give an aqueous humor concn of 3.2 mM in young (4-6 weeks of age) and a 3.3 mM in adult (6 months of age) rabbits. Tissues were taken for microscopy at either 6 or 24 hr intracameral hydrogen peroxide. Neither oral nor intravenous 3-aminotriazole alone in adult rabbits, or iv 3-aminotriazole in young rabbits, had any effect on either iris, ciliary process, or corneal endothelial morphology. After oral 3-aminotriazole in adult rabbits, hydrogen peroxide caused highly edematous ciliary processes with dilated vessels; corneal endothelial cells were swollen. ... In non 3-aminotriazole-treated young rabbits, hydrogen peroxide caused only minor morphological changes. In adult animals at 6 and 24 hr after intracameral hydrogen peroxide the ciliary processes were edematous in the absence of 3-aminotriazole; after iv 3-aminotriazole and intracameral hydrogen peroxide the changes were even more marked, with very severe swelling of ciliary processes and corneal endothelial damage. ... In adult animals, the effects of hydrogen peroxide are enhanced in the presence of 3-aminotriazole.
Birnbaum D et al; Curr Eye Res 6 (12): 1403-14 (1987)
/LABORATORY ANIMALS: Acute Exposure/ Amitrole was tested for possible dermal sensitization potential in guinea-pigs using the Magnusson-Kligman maximization test with Freund's adjuvant. The concentrations employed were 2.5% for intracutaneous induction, 25% for topical induction, and 12% for the first and second challenges. Evidence for moderate skin-sensitizing potential in amitrole was found after both challenges.
WHO; Environmental Health Criteria Document No. 158: Amitrole (61-82-5). Available from, as of January 30, 2006: https://www.inchem.org/pages/ehc.html
/LABORATORY ANIMALS: Acute Exposure/ In a study for possible phototoxic potential of amitrol, 20 test subjects were exposed to patches containing amitrole at a level of 1% in an ointment base (hydrous eucerin) over a period of 48 hours. The treatment areas were then irradiated with ultraviolet light (UVA and UVB), and the dermal reaction assessed. No evidence was found for phototoxic skin reactions.
European Chemicals Bureau; IUCLID Dataset, Amitrole (61-82-5) (2000 CD-ROM edition). Available from, as of January 30, 2006: https://ecb.jrc.it/IUCLID-Data-Sheet/61825.pdf
/LABORATORY ANIMALS: Acute Exposure/ Amitrole applied in water formulations to the unabraded skin of rabbits for 24 hr caused a very mild and reversible erythema.
WHO; Environmental Health Criteria Document No. 158: Amitrole (61-82-5). Available from, as of January 30, 2006: https://www.inchem.org/pages/ehc.html
For more Non-Human Toxicity Excerpts (Complete) data for AMITROLE (58 total), please visit the HSDB record page.

13.1.18 Non-Human Toxicity Values

LD50 Mouse oral 14.7 g/kg
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. 13th Edition, Whitehouse Station, NJ: Merck and Co., Inc., 2001., p. 86
LD50 Rat oral 25 g/kg
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. 13th Edition, Whitehouse Station, NJ: Merck and Co., Inc., 2001., p. 86
LD50 Mouse oral 11,000 mg/kg
American Conference of Governmental Industrial Hygienists. Documentation of the TLV's and BEI's with Other World Wide Occupational Exposure Values. CD-ROM Cincinnati, OH 45240-1634 2005., p. 1
LC50 Mouse inhalation 439 mg/cu m/4 hr
American Conference of Governmental Industrial Hygienists. Documentation of the TLV's and BEI's with Other World Wide Occupational Exposure Values. CD-ROM Cincinnati, OH 45240-1634 2005., p. 1
For more Non-Human Toxicity Values (Complete) data for AMITROLE (11 total), please visit the HSDB record page.

13.2 Ecological Information

13.2.1 EPA Ecotoxicity

Pesticide Ecotoxicity Data from EPA

13.2.2 Ecotoxicity Values

LC50 /Coturnix japonica/ (Japanese quail) oral >5000 ppm (no mortality to 5000 ppm), age 12 days.
U.S. Department of the Interior, Fish and Wildlife Service, Bureau of Sports Fisheries and Wildlife. Lethal Dietary Toxicities of Environmental Pollutants to Birds. Special Scientific Report - Wildlife No. 191. Washington, DC: U.S. Government Printing Office, 1975., p. 9
LC50 /Phasianus colchicus/ (Ring-necked pheasant) >5000 ppm (no mortality to 5000 ppm), age 10 days.
U.S. Department of the Interior, Fish and Wildlife Service, Bureau of Sports Fisheries and Wildlife. Lethal Dietary Toxicities of Environmental Pollutants to Birds. Special Scientific Report - Wildlife No. 191. Washington, DC: U.S. Government Printing Office, 1975., p. 9
LC50 Gammarus fasciatus (Scud) >10 mg/L/96 hr at 18 °C /static conditions without aeration/
U.S. Department of Interior, Fish and Wildlife Service. Handbook of Acute Toxicity of Chemicals to Fish and Aquatic Invertebrates. Resource Publication No. 137. Washington, DC: U.S. Government Printing Office, 1980., p. 81
LC50 /Pimephales promelas/ (Fathead minnow, weight 1.2 g) >100 mg/L/96 hr at 18 °C. /static conditions without aeration/
U.S. Department of Interior, Fish and Wildlife Service. Handbook of Acute Toxicity of Chemicals to Fish and Aquatic Invertebrates. Resource Publication No. 137. Washington, DC: U.S. Government Printing Office, 1980., p. 81
For more Ecotoxicity Values (Complete) data for AMITROLE (29 total), please visit the HSDB record page.

13.2.3 Ecotoxicity Excerpts

/BIRDS and MAMMALS/ Acute symptoms: ataxia, weakness, slight wing drop, during first 3 days after single oral admin only in /mallard ducks/.
U. S. Department of the Interior, Fish & Wildlife Service, Bureau of Sport Fisheries & Wildlife. Handbook of Toxicity of Pesticides to Wildlife. Washington, D. C.: U. S. Government Printing Office, 1970., p. 19
/AQUATIC SPECIES/ /Investigators/ exposed fry of bluegill sunfish, green sunfish and lake chub sucker fish to amitrole at 50 mg/liter for 8 days and reported no deaths. Young bluegill survived a 12-day exposure to 25 mg/liter, although some deaths occurred at higher concentrations.
WHO; Environmental Health Criteria Document No. 158: Amitrole (61-82-5). Available from, as of January 30, 2006: https://www.inchem.org/pages/ehc.html
/AQUATIC SPECIES/ /Investigators/ exposed yearling Coho salmon (Oncorhynchus kisutch) to Amitrole-T at concentrations of between 0.25 and 200 mg/liter. Transfer of the young salmon to sea water with comparable concentrations of amitrole increased the toxic effect of the compound; 56% of fish survived 336 hr in sea water containing 25 mg amitrole/liter and 12.5% survived 50 mg/liter. According to the authors, deaths occurred within 24-48 hr. Smoltification, the adaptation of young salmon to sea water, is under thyroid control. The goitrogenic properties of amitrole may explain the effect.
WHO; Environmental Health Criteria Document No. 158: Amitrole (61-82-5). Available from, as of January 30, 2006: https://www.inchem.org/pages/ehc.html
/OTHER TERRESTRIAL SPECIES/ Foliar and soil application in concentrations below the recommended rate of the herbicide 3-amino-1,2,4-triazole to the host plant Phaseolus vulgaris results in structural alteration of the protein-synthesizing apparatus of midgut and salivary gland cells of the phytophagous spider mite Tetranychus urticae (Acari: Tetranychidae) independent of its mode of application. With prolonged incubation times cytological defects become more intense, and spread to more cells and tissues. Resultant effects on yolk and egg formation were expressed as an inhibition of egg deposition that led to a decrease in the reproduction rat of Tetranychus urticae. ...
Mothes-Wagner U et al; Exp Appl Acarol 8 (1-2): 27-40 (1990)

13.2.4 ICSC Environmental Data

The substance is toxic to aquatic organisms. This substance does enter the environment under normal use. Great care, however, should be taken to avoid any additional release, for example through inappropriate disposal.

13.2.5 Environmental Fate / Exposure Summary

2-Amino-1,3,4-triazole's production may result in its release to the environment through various waste streams; it's use as a non-selective herbicide used on annual grasses and broadleaf weeds will result in its direct release to the environment. If released to air, a vapor pressure of 4.4X10-7 mm Hg at 25 °C indicates 2-amino-1,3,4-triazole will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase 2-amino-1,3,4-triazole will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 3 days. Particulate-phase 2-amino-1,3,4-triazole will be removed from the atmosphere by wet and dry deposition. If released to soil, 2-amino-1,3,4-triazole is expected to have high to very high mobility based upon Koc values of 11.6, 29.7, 20.2, and 51.2 measured in silty clay, sandy loam, sand, and silt soils, respectively. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 2.2X10-13 atm-cu m/mole. Aerobic biodegradation studies conducted under laboratory conditions and field dissipation studies indicate that 2-amino-1,3,4-triazole biodegrades in soils with a half-life of approximately 3 weeks. If released into water, 2-amino-1,3,4-triazole is not expected to adsorb to suspended solids and sediment in the water column based upon the Koc data. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. The half-life of 2-amino-1,3,4-triazole was reported as 57-74 days in aerobic aquatic degradation studies. 2-Amino-1,3,4-triazole did not hydrolyze or undergo photolysis in laboratory studies at pH 5,7, and 9, indicating that hydrolysis and photolysis are not important environmental fate processes for this compound. BCF values of <3 measured in fish suggest bioconcentration in aquatic organisms is low. Occupational exposure to 2-amino-1,3,4-triazole may occur through inhalation of dusts or dermal contact with this compound at workplaces where it is produced or used as an herbicide. (SRC)

13.2.6 Artificial Pollution Sources

2-Amino-1,3,4-triazole's production may result in its release to the environment through various waste streams; it's use as a non-selective herbicide used on annual grasses and broadleaf weeds(1) will result in its direct release to the environment(SRC).
(1) USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from the Database Query page at https://www.epa.gov/pesticides/reregistration/status.htm as of Jan 31, 2006.

13.2.7 Environmental Fate

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values of 11.6, 29.7, 20.2, and 51.2, measured in four soils(2), indicates that 2-amino-1,3,4-triazole is expected to have high to very high mobility in soil(SRC). Volatilization of 2-amino-1,3,4-triazole from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 2.2X10-13 atm-cu m/mole(SRC), derived from its vapor pressure, 4.4X10-7 mm Hg(2), and water solubility, 2.8X10+5 mg/L(2). 2-Amino-1,3,4-triazole is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(2). Field dissipation studies and laboratory degradation studies indicate that 2-amino-1,3,4-triazole is not highly persistent in the environment(2). Aerobic biodegradation studies conducted under laboratory conditions indicated that the half-life of 2-amino-1,3,4-triazole in soil is approximately 22-26 days, while field dissipation studies conducted at sites in Oregon and Washington indicate a 50% dissipation time (DT50) of 17-21 days(2).
(1) Swann RL et al; Res Rev 85: 17-28 (1983)
(2) USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from the Database Query page at https://www.epa.gov/pesticides/reregistration/status.htm as of Jan 31, 2006.
AQUATIC FATE: Based on a classification scheme(1), Koc values of 11.6 to 51.2(2), indicate that 2-amino-1,3,4-triazole is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 2.2X10-13 atm-cu m/mole(SRC), derived from its vapor pressure, 4.4X10-7 mm Hg(2), and water solubility, 2.8X10+5 mg/L(2). According to a classification scheme(4), BCF values of less than 3 measured in fish(5), suggest bioconcentration in aquatic organisms is low(SRC). 2-Amino-1,3,4-triazole does not undergo hydrolysis or photolysis in aqueous systems, and the half-life of 2-amino-1,3,4-triazole was reported as 57-74 days in aerobic aquatic degradation studies(2).
(1) Swann RL et al; Res Rev 85: 17-28 (1983)
(2) USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from the Database Query page at https://www.epa.gov/pesticides/reregistration/status.htm as of Jan 31, 2006.
(3) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 4-9, 15-1 to 15-29 (1990)
(4) Franke C et al; Chemosphere 29: 1501-14 (1994)
(5) Chemicals Inspection and Testing Institute. Japan Chemical Industry Ecology - Toxicology and Information Center. ISBN 4-89074-101-1 (1992)
ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2-amino-1,3,4-triazole, which has a vapor pressure of 4.4X10-7 mm Hg at 25 °C(2), is expected to exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase 2-amino-1,3,4-triazole is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 3 days(SRC), calculated from its rate constant of 5.5X10-12 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase 2-amino-1,3,4-triazole may be removed from the air by wet and dry deposition(SRC).
(1) Bidleman TF; Environ Sci Technol 22: 361-367 (1988)
(2) USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from the Database Query page at https://www.epa.gov/pesticides/reregistration/status.htm as of Jan 31, 2006.
(3) Meylan WM, Howard PH; Chemosphere 26: 2293-99 (1993)
...DISAPPEARANCE OF [5-(14)C]-AMITROLE FROM CORN PLANTS IN APPROX 6 WK WITH HALF-LIFE OF ABOUT 8 DAYS. DISAPPEARANCE WAS ALSO OBSERVED FROM SOYBEAN BUT @ MUCH SLOWER RATE.../&/ IN COTTON 4 DAYS AFTER TREATMENT.
Kearney, P.C., and D. D. Kaufman (eds.) Herbicides: Chemistry, Degredation and Mode of Action. Volumes 1 and 2. 2nd ed. New York: Marcel Dekker, Inc., 1975., p. 379

13.2.8 Environmental Biodegradation

WHATEVER THE MECHANISM WHEREBY TRIAZOLE RING IS OPENED, THERE APPEARS TO BE LITTLE DOUBT THAT RING OPENING DOES OCCUR RAPIDLY IN SOILS & RESULTING PRODUCTS (UREA, CYANAMID, & NITROGEN) SHOULD BE READILY METABOLIZED BY SOIL MICROORGANISMS.
Kearney, P.C., and D. D. Kaufman (eds.) Herbicides: Chemistry, Degredation and Mode of Action. Volumes 1 and 2. 2nd ed. New York: Marcel Dekker, Inc., 1975., p. 384
AEROBIC: The microbial breakdown of 2-amino-1,3,4-triazole in warm, moist soil has been reported to be 2 to 3 weeks(1). 2-Amino-1,3,4-triazole was found to be readily attacked microbiologically in Honeoye silt loam soil as measured by carbon dioxide evolution (radio-labelled) and comparison to autoclave soil samples(2). In a river die-away test, carbon dioxide evolution was 10 percent greater in river water containing 20 ppm 2-amino-1,3,4-triazole as compared to control for the first week of incubation; however, the difference decreased and became negligible after 60 days(3). Nitrifying organisms in activated sludge were found to be relatively intolerant to 2-amino-1,3,4-triazole levels above a few ppm with the effect appearing bacteriostatic(3). Carbonaceous oxidation in activated sludge showed inhibition at 2-amino-1,3,4-triazole levels above 10 ppm(3). 2-Amino-1,3,4-triazole showed no evidence of degradation or inhibitory effects in anaerobic digestion tests(3). In 2-amino-1,3,4-triazole degradation studies using Hagerstown silty clay loam soil, 50% of applied 2-amino-1,3,4-triazole (radio-labelled) was evolved as carbon dioxide after 3 days of incubation and 70% was evolved as carbon dioxide after 20 days while no carbon dioxide was evolved in autoclaved soil(4).
(1) Weed Science Society of America; Herbicide Handbook 5th ed Champaign, IL (1983)
(2) MacRae IC, Alexander M; J Agric Food Chem 13: 72 (1965)
(3) Ludzak FJ, Mandia JW; Purdue Univ Eng Bull Ext Ser 109: 540 (1962)
(4) Kaufman DD et al; Weed Sci 16: 266 (1968)
(1) USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from the Database Query page at https://www.epa.gov/pesticides/reregistration/status.htm as of Jan 31, 2006.
(2) Dakhel N et al; Biol Fertil Soils 33: 490-494 (2001)
(3) Oesterreich T et al; Chemosphere 38: 379-392 (1999)

13.2.9 Environmental Abiotic Degradation

LOSS FROM PHOTODECOMPOSITION & /IS/ MINOR.
Weed Science Society of America. Herbicide Handbook. 4th ed. Champaign, IL: Weed Science Society of America, 1979. of America, 1979., p. 19
The rate constant for the vapor-phase reaction of 2-amino-1,3,4-triazole with photochemically-produced hydroxyl radicals has been estimated as 5.5X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 3 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). 14C labeled 2-amino-1,3,4-triazole did not degrade in filter-sterilized aqueous buffer solutions (pH 5, 7, and 9) during 30 days of dark incubation at approximately 25 °C(2). 2-Amino-1,3,4-triazole comprised essentially 100% of the recovered radioactivity at all sampling intervals(2). In a second study, 2-amino-1,3,4-triazole was stable to hydrolysis in aqueous buffered pH 5, 7, and 9 solutions that were incubated in the dark for 34 days at 25 °C(2). 2-Amino-1,3,4-triazole is considered stable to degradation by aqueous photolysis. 2-Amino-1,3,4-triazole did not substantially photodegrade in filter-sterilized aqueous buffer solutions (pH 5, 7, and 9) during 30 days of artificial light exposure (UV glass-filtered xenon arc lamp) at 25 °C(2). The rate constant for the aqueous reaction between 2-amino-1,3,4-triazole and photooxidatively generated peroxy radicals has been theoretically estimated to be 2X10+6/M-hr(3); assuming the peroxy radical concentration in brightly sunlit waters is 1X10-9 M, a half-life of about 350 hours (14.5 days) in bright sunlight is estimated(SRC). 2-Amino-1,3,4-triazole photodegraded with an observed half-life of >30 days on sandy loam soil that was irradiated for a 12-hour period with artificial light (xenon arc lamp) for 30 days at 25 °C(2). In contrast, 2-amino-1,3,4-triazole did not degrade on sandy loam soil incubated for 30 days at 25 °C in darkness. The only degradate identified in the irradiated samples was 1,2,4-triazole (maximum concentration of 9.9% at 30 days).
(1) Meylan WM, Howard PH; Chemosphere 26: 2293-99 (1993)
(2) USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from the Database Query page at https://www.epa.gov/pesticides/reregistration/status.htm as of Jan 31, 2006.
(3) Jaber HM et al; Data acquisition for environmental transport and fate screening for compounds of interest to the Office of Emergency and Remedial Response pp 156 USEPA-600/6-84-011 (1984)

13.2.10 Environmental Bioconcentration

Carp exposed to 2 and 0.2 mg/L 2-amino-1,3,4-triazole over a 6 week incubation period had reported BCF values of <0.3 and <3, respectively(1). According to a classification scheme(2), these BCF values suggest bioconcentration in aquatic organisms is low(SRC).
(1) Chemicals Inspection and Testing Institute. Japan Chemical Industry Ecology - Toxicology and Information Center. ISBN 4-89074-101-1 (1992)
(2) Franke C et al; Chemosphere 29: 1501-14 (1994)

13.2.11 Soil Adsorption / Mobility

Based on batch equilibrium experiments, 2-amino-1,3,4-triazole (dissolved in 1% sodium azide solutions) was determined to be mobile in silty clay, sandy loam, sand, and silt soils, with Freundlich Kf values of 0.152-0.922 ml/g(1). Freundlich Kf values were 0.714 (1/n = 0.7671) for the silty clay soil, 0.223 (1/n = 0.8549) for the sandy loam soil, 0.152 (1/n = 0.8722) for the sand soil, and 0.922 (1/n = 0.8590) for the silt soil; corresponding Koc values were 11.6, 29.7, 20.2, and 51.2, respectively(1). 2-Amino-1,3,4-triazole was mobile in these same soils when the soils were acidified to approximately pH 4.5; Freundlich Kf values ranged from 0.575-2.28. In another batch equilibrium study, 2-amino-1,3,4-triazole was determined to be mobile in Plainsfield sand (Kf = 0.685, 1/n = 0.7975), California sandy loam (Kf = 3.52, 1/n = 0.6487), Kewaunee silty clay loam (K = 1.57, 1/n = 0.8563), and Plano silt loam (Kf = 3.79, 1/n = 0.7739) soils(1). No discernible correlation between adsorption and either organic carbon content or CEC of the soils was observed(1). According to a classification scheme(2), these Koc values suggests that 2-amino-1,3,4-triazole is expected to have very high to high mobility in soil(SRC).
(1) USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from the Database Query page at https://www.epa.gov/pesticides/reregistration/status.htm as of Jan 31, 2006.
(2) Swann RL et al; Res Rev 85: 17-28 (1983)

13.2.12 Volatilization from Water / Soil

The Henry's Law constant for 2-amino-1,3,4-triazole is estimated as 2.2X10-13 atm-cu m/mole(SRC) derived from its vapor pressure, 4.4X10-7 mm Hg(1), and water solubility, 2.8X10+5 mg/L(1). This Henry's Law constant indicates that 2-amino-1,3,4-triazole is expected to essentially be non-volatile from water and moist soil surfaces(2). 2-Amino-1,3,4-triazole is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).
(1) USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from the Database Query page at https://www.epa.gov/pesticides/reregistration/status.htm as of Jan 31, 2006.
(2) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 15-1 to 15-29 (1990)

13.2.13 Environmental Water Concentrations

GROUNDWATER: 2-Amino-1,3,4-triazole was identified, not quantified, in groundwater from the Netherlands(1). Groundwater and surface water sites in France contained 2-amino-1,3,4-triazole at levels of 300-500 ng/L(2). 2-Amino-1,3,4-triazole was identified in groundwater wells from agricultural areas of Ontario, Canada at levels of 0.1-1.0 ug/L and 1-10 mg/L(3).
(1) Beitz H et al; in Chemistry of Plant Protection. Borner H ed. Berlin, Germany: Springer-Verlag. 9(pesticides in ground and surface water): 3-56 (1994)
(2) Duguet JP et al; Water Supply 12: SS11/1-SS11/5 (1994)
(3) Frank R et al; Pestic Monit J 13: 120-127 (1979)

13.2.14 Food Survey Values

2-Amino-1,3,4-triazole residues have been found in marketed cranberries (1958-1959)(1). 2-Amino-1,3,4-triazole is currently a non-food use herbicide used primarily in industrial areas (outdoors), non-agricultural rights-of-way, fencerows, hedgerows, non-agricultural uncultivated areas, soils, ornamental and/or shade trees, and ornamental shrubs and vines(2); therefore, residues on food products are not expected(SRC).
(1) IARC; Some Anti-thyroid and Related Substances, Nitrofurans and Industrial Chemicals 7: 31 (1974)
(2) USEPA; Reregistration Eligibility Decisions (REDs) Database on Amitrole, List A, Case 0095. August, 1996. (61-82-5). Available from the Database Query page at https://www.epa.gov/pesticides/reregistration/status.htm as of Jan 31, 2006.

13.2.15 Probable Routes of Human Exposure

NIOSH (NOES Survey 1981-1983) has statistically estimated that 693 workers (24 of these are female) are potentially exposed to 2-amino-1,3,4-triazole in the US(1). Occupational exposure to 2-amino-1,3,4-triazole may occur through inhalation of dusts or dermal contact with this compound at workplaces where it is produced or used as an herbicide(SRC).
(1) NIOSH; International Safety Cards. Triazole, 3-Amino-, S-. 61-82-5. Available at: https://www.cdc.gov/noes/noes1/84718sic.html as of Jan 9, 2006.

14 Associated Disorders and Diseases

Associated Occupational Diseases with Exposure to the Compound
Contact dermatitis, allergic [Category: Skin Disease]

15 Literature

15.1 Consolidated References

15.2 NLM Curated PubMed Citations

15.3 Springer Nature References

15.4 Thieme References

15.5 Wiley References

15.6 Chemical Co-Occurrences in Literature

15.7 Chemical-Gene Co-Occurrences in Literature

15.8 Chemical-Disease Co-Occurrences in Literature

16 Patents

16.1 Depositor-Supplied Patent Identifiers

16.2 WIPO PATENTSCOPE

16.3 Chemical Co-Occurrences in Patents

16.4 Chemical-Disease Co-Occurrences in Patents

16.5 Chemical-Gene Co-Occurrences in Patents

17 Interactions and Pathways

17.1 Protein Bound 3D Structures

17.1.1 Ligands from Protein Bound 3D Structures

PDBe Ligand Code
PDBe Structure Code
PDBe Conformer

17.2 Chemical-Target Interactions

17.3 Pathways

18 Biological Test Results

18.1 BioAssay Results

19 Classification

19.1 MeSH Tree

19.2 NCI Thesaurus Tree

19.3 ChEBI Ontology

19.4 KEGG: EDC

19.5 KEGG: Pesticides

19.6 ChemIDplus

19.7 CAMEO Chemicals

19.8 ChEMBL Target Tree

19.9 UN GHS Classification

19.10 EPA CPDat Classification

19.11 NORMAN Suspect List Exchange Classification

19.12 EPA DSSTox Classification

19.13 International Agency for Research on Cancer (IARC) Classification

19.14 EPA TSCA and CDR Classification

19.15 EPA Substance Registry Services Tree

19.16 MolGenie Organic Chemistry Ontology

20 Information Sources

  1. Australian Industrial Chemicals Introduction Scheme (AICIS)
  2. CAMEO Chemicals
    LICENSE
    CAMEO Chemicals and all other CAMEO products are available at no charge to those organizations and individuals (recipients) responsible for the safe handling of chemicals. However, some of the chemical data itself is subject to the copyright restrictions of the companies or organizations that provided the data.
    https://cameochemicals.noaa.gov/help/reference/terms_and_conditions.htm?d_f=false
    CAMEO Chemical Reactivity Classification
    https://cameochemicals.noaa.gov/browse/react
  3. ILO-WHO International Chemical Safety Cards (ICSCs)
  4. CAS Common Chemistry
    LICENSE
    The data from CAS Common Chemistry is provided under a CC-BY-NC 4.0 license, unless otherwise stated.
    https://creativecommons.org/licenses/by-nc/4.0/
  5. ChemIDplus
    ChemIDplus Chemical Information Classification
    https://pubchem.ncbi.nlm.nih.gov/source/ChemIDplus
  6. DTP/NCI
    LICENSE
    Unless otherwise indicated, all text within NCI products is free of copyright and may be reused without our permission. Credit the National Cancer Institute as the source.
    https://www.cancer.gov/policies/copyright-reuse
  7. EPA Chemicals under the TSCA
    EPA TSCA Classification
    https://www.epa.gov/tsca-inventory
  8. EPA DSSTox
    CompTox Chemicals Dashboard Chemical Lists
    https://comptox.epa.gov/dashboard/chemical-lists/
  9. European Chemicals Agency (ECHA)
    LICENSE
    Use of the information, documents and data from the ECHA website is subject to the terms and conditions of this Legal Notice, and subject to other binding limitations provided for under applicable law, the information, documents and data made available on the ECHA website may be reproduced, distributed and/or used, totally or in part, for non-commercial purposes provided that ECHA is acknowledged as the source: "Source: European Chemicals Agency, http://echa.europa.eu/". Such acknowledgement must be included in each copy of the material. ECHA permits and encourages organisations and individuals to create links to the ECHA website under the following cumulative conditions: Links can only be made to webpages that provide a link to the Legal Notice page.
    https://echa.europa.eu/web/guest/legal-notice
  10. FDA Global Substance Registration System (GSRS)
    LICENSE
    Unless otherwise noted, the contents of the FDA website (www.fda.gov), both text and graphics, are not copyrighted. They are in the public domain and may be republished, reprinted and otherwise used freely by anyone without the need to obtain permission from FDA. Credit to the U.S. Food and Drug Administration as the source is appreciated but not required.
    https://www.fda.gov/about-fda/about-website/website-policies#linking
  11. Hazardous Substances Data Bank (HSDB)
  12. New Zealand Environmental Protection Authority (EPA)
    LICENSE
    This work is licensed under the Creative Commons Attribution-ShareAlike 4.0 International licence.
    https://www.epa.govt.nz/about-this-site/general-copyright-statement/
  13. NJDOH RTK Hazardous Substance List
  14. Occupational Safety and Health Administration (OSHA)
    LICENSE
    Materials created by the federal government are generally part of the public domain and may be used, reproduced and distributed without permission. Therefore, content on this website which is in the public domain may be used without the prior permission of the U.S. Department of Labor (DOL). Warning: Some content - including both images and text - may be the copyrighted property of others and used by the DOL under a license.
    https://www.dol.gov/general/aboutdol/copyright
  15. Risk Assessment Information System (RAIS)
    LICENSE
    This work has been sponsored by the U.S. Department of Energy (DOE), Office of Environmental Management, Oak Ridge Operations (ORO) Office through a joint collaboration between United Cleanup Oak Ridge LLC (UCOR), Oak Ridge National Laboratory (ORNL), and The University of Tennessee, Ecology and Evolutionary Biology, The Institute for Environmental Modeling (TIEM). All rights reserved.
    https://rais.ornl.gov/
  16. California Safe Cosmetics Program (CSCP) Product Database
  17. EU Pesticides Database
  18. Burnham Center for Chemical Genomics
  19. The National Institute for Occupational Safety and Health (NIOSH)
    LICENSE
    The information provided using CDC Web site is only intended to be general summary information to the public. It is not intended to take the place of either the written law or regulations.
    https://www.cdc.gov/Other/disclaimer.html
  20. California Office of Environmental Health Hazard Assessment (OEHHA)
  21. ChEBI
  22. NCI Thesaurus (NCIt)
    LICENSE
    Unless otherwise indicated, all text within NCI products is free of copyright and may be reused without our permission. Credit the National Cancer Institute as the source.
    https://www.cancer.gov/policies/copyright-reuse
  23. Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
    LICENSE
    Copyright (c) 2022 Haz-Map(R). All rights reserved. Unless otherwise indicated, all materials from Haz-Map are copyrighted by Haz-Map(R). No part of these materials, either text or image may be used for any purpose other than for personal use. Therefore, reproduction, modification, storage in a retrieval system or retransmission, in any form or by any means, electronic, mechanical or otherwise, for reasons other than personal use, is strictly prohibited without prior written permission.
    https://haz-map.com/About
  24. ChEMBL
    LICENSE
    Access to the web interface of ChEMBL is made under the EBI's Terms of Use (http://www.ebi.ac.uk/Information/termsofuse.html). The ChEMBL data is made available on a Creative Commons Attribution-Share Alike 3.0 Unported License (http://creativecommons.org/licenses/by-sa/3.0/).
    http://www.ebi.ac.uk/Information/termsofuse.html
  25. Comparative Toxicogenomics Database (CTD)
    LICENSE
    It is to be used only for research and educational purposes. Any reproduction or use for commercial purpose is prohibited without the prior express written permission of NC State University.
    http://ctdbase.org/about/legal.jsp
  26. Crystallography Open Database (COD)
    LICENSE
    All data in the COD and the database itself are dedicated to the public domain and licensed under the CC0 License. Users of the data should acknowledge the original authors of the structural data.
    https://creativecommons.org/publicdomain/zero/1.0/
  27. EPA Chemical and Products Database (CPDat)
  28. EPA Pesticide Ecotoxicity Database
  29. NORMAN Suspect List Exchange
    LICENSE
    Data: CC-BY 4.0; Code (hosted by ECI, LCSB): Artistic-2.0
    https://creativecommons.org/licenses/by/4.0/
    Amitrole
    NORMAN Suspect List Exchange Classification
    https://www.norman-network.com/nds/SLE/
  30. Hazardous Chemical Information System (HCIS), Safe Work Australia
  31. NITE-CMC
    3-Amino-1H-1,2,4-triazole, (alias Amitrole) - FY2009 (Revised classification)
    https://www.chem-info.nite.go.jp/chem/english/ghs/09-mhlw-2063e.html
  32. Regulation (EC) No 1272/2008 of the European Parliament and of the Council
    LICENSE
    The copyright for the editorial content of this source, the summaries of EU legislation and the consolidated texts, which is owned by the EU, is licensed under the Creative Commons Attribution 4.0 International licence.
    https://eur-lex.europa.eu/content/legal-notice/legal-notice.html
    amitrole (ISO); 1,2,4-triazol-3-ylamine
    https://eur-lex.europa.eu/eli/reg/2008/1272/oj
  33. IUPAC Digitized pKa Dataset
  34. MassBank of North America (MoNA)
    LICENSE
    The content of the MoNA database is licensed under CC BY 4.0.
    https://mona.fiehnlab.ucdavis.edu/documentation/license
  35. Human Metabolome Database (HMDB)
    LICENSE
    HMDB is offered to the public as a freely available resource. Use and re-distribution of the data, in whole or in part, for commercial purposes requires explicit permission of the authors and explicit acknowledgment of the source material (HMDB) and the original publication (see the HMDB citing page). We ask that users who download significant portions of the database cite the HMDB paper in any resulting publications.
    http://www.hmdb.ca/citing
  36. NIST Mass Spectrometry Data Center
    LICENSE
    Data covered by the Standard Reference Data Act of 1968 as amended.
    https://www.nist.gov/srd/public-law
  37. SpectraBase
  38. International Agency for Research on Cancer (IARC)
    LICENSE
    Materials made available by IARC/WHO enjoy copyright protection under the Berne Convention for the Protection of Literature and Artistic Works, under other international conventions, and under national laws on copyright and neighbouring rights. IARC exercises copyright over its Materials to make sure that they are used in accordance with the Agency's principles. All rights are reserved.
    https://publications.iarc.fr/Terms-Of-Use
    IARC Classification
    https://www.iarc.fr/
  39. Japan Chemical Substance Dictionary (Nikkaji)
  40. Joint FAO/WHO Expert Committee on Food Additives (JECFA)
    LICENSE
    Permission from WHO is not required for the use of WHO materials issued under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Intergovernmental Organization (CC BY-NC-SA 3.0 IGO) licence.
    https://www.who.int/about/policies/publishing/copyright
  41. USGS Columbia Environmental Research Center
  42. KEGG
    LICENSE
    Academic users may freely use the KEGG website. Non-academic use of KEGG generally requires a commercial license
    https://www.kegg.jp/kegg/legal.html
  43. MassBank Europe
  44. Metabolomics Workbench
  45. Protein Data Bank in Europe (PDBe)
  46. RCSB Protein Data Bank (RCSB PDB)
    LICENSE
    Data files contained in the PDB archive (ftp://ftp.wwpdb.org) are free of all copyright restrictions and made fully and freely available for both non-commercial and commercial use. Users of the data should attribute the original authors of that structural data.
    https://www.rcsb.org/pages/policies
  47. Springer Nature
  48. Thieme Chemistry
    LICENSE
    The Thieme Chemistry contribution within PubChem is provided under a CC-BY-NC-ND 4.0 license, unless otherwise stated.
    https://creativecommons.org/licenses/by-nc-nd/4.0/
  49. Wikidata
  50. Wikipedia
  51. Wiley
  52. Medical Subject Headings (MeSH)
    LICENSE
    Works produced by the U.S. government are not subject to copyright protection in the United States. Any such works found on National Library of Medicine (NLM) Web sites may be freely used or reproduced without permission in the U.S.
    https://www.nlm.nih.gov/copyright.html
  53. PubChem
  54. GHS Classification (UNECE)
  55. EPA Substance Registry Services
  56. MolGenie
    MolGenie Organic Chemistry Ontology
    https://github.com/MolGenie/ontology/
  57. PATENTSCOPE (WIPO)
  58. NCBI
CONTENTS