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Hafnium

PubChem CID
23986
Structure
Hafnium_small.png
Molecular Formula
Synonyms
  • HAFNIUM
  • 7440-58-6
  • HF
  • Celtium
  • Hafnium, elemental
Molecular Weight
178.49 g/mol
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Element Name
Dates
  • Create:
    2005-03-26
  • Modify:
    2025-01-18
Description
Hafnium powder, dry, is a grayish metallic colored powder. Dust from dry powder may be ignited by static electricity. The dry powder reacts with moisture to produce hydrogen, a flammable gas. The heat from this reaction may be sufficient to ignite the hydrogen. It does not appreciably react with large quantities of water.
Grayish powdery solid wetted with water.
Hafnium atom is a titanium group element atom.
See also: Hafnium dihydride (annotation moved to) ... View More ...

1 Structures

1.1 2D Structure

Chemical Structure Depiction
Hafnium.png

1.2 Crystal Structures

2 Names and Identifiers

2.1 Computed Descriptors

2.1.1 IUPAC Name

hafnium
Computed by Lexichem TK 2.7.0 (PubChem release 2021.10.14)

2.1.2 InChI

InChI=1S/Hf
Computed by InChI 1.0.6 (PubChem release 2021.10.14)

2.1.3 InChIKey

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

2.1.4 SMILES

[Hf]
Computed by OEChem 2.3.0 (PubChem release 2024.12.12)

2.2 Molecular Formula

Hf
Computed by PubChem 2.2 (PubChem release 2021.10.14)

2.3 Other Identifiers

2.3.1 CAS

7440-58-6

2.3.2 Deprecated CAS

412316-00-8

2.3.3 European Community (EC) Number

2.3.4 UNII

2.3.5 UN Number

2.3.6 ChEBI ID

2.3.7 DSSTox Substance ID

2.3.8 HMDB ID

2.3.9 ICSC Number

2.3.10 NCI Thesaurus Code

2.3.11 Nikkaji Number

2.3.12 Wikidata

2.3.13 Wikipedia

2.4 Synonyms

2.4.1 MeSH Entry Terms

Hafnium

2.4.2 Depositor-Supplied Synonyms

3 Chemical and Physical Properties

3.1 Computed Properties

Property Name
Molecular Weight
Property Value
178.49 g/mol
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
Hydrogen Bond Donor Count
Property Value
0
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Hydrogen Bond Acceptor Count
Property Value
0
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
179.94656 Da
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
Monoisotopic Mass
Property Value
179.94656 Da
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
Topological Polar Surface Area
Property Value
0 Ų
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Heavy Atom Count
Property Value
1
Reference
Computed by PubChem
Property Name
Formal Charge
Property Value
0
Reference
Computed by PubChem
Property Name
Complexity
Property Value
0
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

Hafnium powder, dry, is a grayish metallic colored powder. Dust from dry powder may be ignited by static electricity. The dry powder reacts with moisture to produce hydrogen, a flammable gas. The heat from this reaction may be sufficient to ignite the hydrogen. It does not appreciably react with large quantities of water.
Grayish powdery solid wetted with water.
Other Solid
Highly lustrous, ductile, grayish solid; [NIOSH]
Solid
GREY POWDER.
Highly lustrous, ductile, grayish solid.

3.2.2 Color / Form

Gray crystals
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 14th Edition. John Wiley & Sons, Inc. New York, NY 2001., p. 554
Highly lustrous metal of hexagonal crystal structure
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. 818
Hard, shiny, ductile metal with a color very similar to that of stainless steel ... hafnium sponge metal is a dull powder gray
Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V12: 863 (1994)
Highly lustrous, ductile, grayish solid.
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. 2004-103 (2003).
Crystallizes in a...cubic system which transforms to a hexagonal close-packed system below 2033 K.
Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V12: 863 (1994)

3.2.3 Boiling Point

8316 °F at 760 mmHg (NIOSH, 2024)
4603 °C
Lide, DR (ed.). CRC Handbook of Chemistry and Physics. 81st Edition. CRC Press LLC, Boca Raton: FL 2000, p. 4-62
4602 °C
8316 °F

3.2.4 Melting Point

4041 °F (NIOSH, 2024)
2233 °C
Lide, DR (ed.). CRC Handbook of Chemistry and Physics. 81st Edition. CRC Press LLC, Boca Raton: FL 2000, p. 4-62
2222 °C
4041 °F

3.2.5 Solubility

Insoluble (NIOSH, 2024)
Hafnium is slowly attacked by concentrated sulfuric acid. Hafnium is unaffected by nitric acid in all concentrations. It is resistant to dilute solutions of hydrochloric acid and sulfuric acid. Hafnium is attacked by all mineral acids if traces of fluorides are present. Hafnium is very resistant to attack by alkalies.
Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V12: 863 (1994)
Lide, DR (ed.). CRC Handbook of Chemistry and Physics. 81st Edition. CRC Press LLC, Boca Raton: FL 2000, p. 4-62
Solubility in water: none
Insoluble

3.2.6 Density

13.31 (NIOSH, 2024) - Denser than water; will sink
13.31
Lide, DR (ed.). CRC Handbook of Chemistry and Physics. 81st Edition. CRC Press LLC, Boca Raton: FL 2000, p. 4-14
Zirconium and hafnium chemistries are almost identical ... the density of zirconium is about half that of hafnium.
Lide, DR (ed.). CRC Handbook of Chemistry and Physics. 81st Edition. CRC Press LLC, Boca Raton: FL 2000, p. 4-14
Relative density (water = 1): 13.31

3.2.7 Vapor Pressure

0 mmHg (approx) (NIOSH, 2024)
1X10-05 Pa at 1767 °C; 1X10-04 Pa at 2007 °C
Nielsen RH (2002); Ullman's Encycl Indust Chem 7th ed. (2005). NY, NY: John Wiley & Sons; Hafnium and Hafnium Compounds. Online Posting Date: June 15, 2000.
0 mmHg (approx)

3.2.8 Autoignition Temperature

20 °C for dust cloud
Sunshine, I. (ed.). CRC Handbook of Analytical Toxicology. Cleveland: The Chemical Rubber Co., 1969., p. 633
20 °C

3.2.9 Decomposition

May explosively decompose on shock, friction, or concussion. /Hafnium powder/
IPCS, CEC; International Chemical Safety Card on Hafnium. (October 1995). Available from, as of June 10, 2005: https://www.inchem.org/documents/icsc/icsc/eics0847.htm

3.2.10 Corrosivity

Good corrosion resistance
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 14th Edition. John Wiley & Sons, Inc. New York, NY 2001., p. 554

3.2.11 Other Experimental Properties

Atomic number: 72; ductile; has been successfully alloyed with iron, titanium, niobium, tantalum, and other metals; rapidly absorbs hydrogen to form HfH at 700 °C; halogens react directly to form tetrahalides; properties are considerably influenced by impurities of zirconium present
Lide, DR (ed.). CRC Handbook of Chemistry and Physics. 81st Edition. CRC Press LLC, Boca Raton: FL 2000, p. 4-14
Standard molar enthalpy of formation (kJ/mol at 298.15 K): 0 (crystal), 619.2 (gas); standard molar Gibbs energy of formation (kJ/mol at 298.15 K): 576.5 (gas); standard molar entropy (J/mol-K at 298.15 K): 43.6 (crystal), 186.9 (gas); molar heat capacity at constant pressure (mol/K at 298.15 K): 25.7 (crystal), 20.8 (gas)
Lide, DR (ed.). CRC Handbook of Chemistry and Physics. 81st Edition. CRC Press LLC, Boca Raton: FL 2000, p. 5-19
High thermal neutron cross-section (115 barns); high strength
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 14th Edition. John Wiley & Sons, Inc. New York, NY 2001., p. 554
Six naturally occurring isotopes: 180 (35.22%); 178 (27.1%); 177 (18.56%); 179 (13.75%); 176 (5.21%); 174 (0.163%; alpha-emitter...); artificial isotopes: 157; 158; 168-173; 175; 181-183.
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. 818
For more Other Experimental Properties (Complete) data for HAFNIUM, ELEMENTAL (8 total), please visit the HSDB record page.

3.3 SpringerMaterials Properties

3.4 Chemical Classes

Metals -> Elements, Metallic

5 Chemical Vendors

6 Drug and Medication Information

6.1 FDA National Drug Code Directory

6.2 Drug Labels

Homeopathic product and label

7 Food Additives and Ingredients

7.1 Associated Foods

8 Minerals

2 of 2
Mineral Description
The principal economic source of zirconium is the zirconium silicate mineral, zircon (ZrSiO4). Zircon is the primary source of all hafnium. Zirconium and hafnium are contained in zircon at a ratio of about 50 to 1. Zircon is a coproduct or byproduct of the mining and processing of heavy-mineral sands for the titanium minerals, ilmenite and rutile, or tin minerals. The major end uses of zircon are refractories, foundry sands (including investment casting), and ceramic opacification. Zircon is also marketed as a natural gemstone, and its oxide is processed to produce the diamond simulant, cubic zirconia. Zirconium is used in nuclear fuel cladding, chemical piping in corrosive environments, heat exchangers, and various specialty alloys. The major end uses of hafnium are in nuclear control rods, nickel-based superalloys, nozzles for plasma arc metal cutting, and high-temperature ceramics.
USGS Mineral Commodity Summaries (PDF links)
USGS Mineral Yearbook (PDF links)
2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019

9 Pharmacology and Biochemistry

9.1 Absorption, Distribution and Excretion

Hafnium can be absorbed into the body by inhalation of its aerosol.
Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. V2 p.725
The whole body retention of 181Hf was studied in marmosets (Callithrex jacchus) and found to be closely similar to that in rats and Chinese hamsters. Limited tissue distribution studies suggest a higher uptake in liver and much lower deposition in skin and muscle in the marmoset as compared to the rat or Chinese hamster. Studies in Chinese hamsters showed that treatment with the chelating agent diethylenetriaminepentaacetic acid resulted in only a small reduction in the whole body retention of 181Hf. The absorption of orally administered 181Hf, in various chemical forms, was found to be between 0.04 and 0.13% of the ingested dose and was unaffected by age between 5 and 21 months but was increased by fasting. The measured absorption of 181Hf in Chinese hamsters and in rats was similar to that of plutonium suggesting that radiohafnium could be used as a surrogate for plutonium for selected studies in human volunteers. /Radiohafnium/
Taylor DM et al; Int J Nucl Med Biol 12 (5): 387-91 (1985)

10 Use and Manufacturing

10.1 Uses

Sources/Uses
Used to make high-temperature alloys, control rods for nuclear reactors, light bulb filaments, capacitors, cemented carbide tools, coatings for rocket engine parts, TV tubes, and x-ray tubes; [Reference #1]
Industrial Processes with risk of exposure

Metal Preparation and Pouring [Category: Foundry]

Shakeout, Cleaning, and Finishing [Category: Foundry]

Metal Machining [Category: Heat or Machine]

Semiconductor Manufacturing [Category: Industry]

Use in control rods in water-cooled nuclear reactors; in gas-filled tubes and incandescent lamps as a scavenger for oxygen and nitrogen; in the manufacture of photographic flash bulbs, light bulb filaments, and in electronic equipment as cathodes and capacitors.
OSHA; Health Guidelines, NIOSH/OSHA/DOE for Hafnium (7440-58-6). Available from, as of July 13, 2005: https://www.osha.gov/SLTC/healthguidelines/hafnium/recognition.html#exposuresources
Use as a substitute for tantalum in cemented carbide tool bits, as a coating on rocket engine parts, and in radio and television tubes, and in X-ray tubes
OSHA; Health Guidelines, NIOSH/OSHA/DOE for Hafnium (7440-58-6). Available from, as of July 13, 2005: https://www.osha.gov/SLTC/healthguidelines/hafnium/recognition.html#exposuresources
Cemented carbide cutting tools
Kirk-Othmer Encyclopedia of Chemical Technology. 3rd ed., Volumes 1-26. New York, NY: John Wiley and Sons, 1978-1984., p. V12 73
The major uses of hafnium involve the metal. The largest use is as an alloying additive (1 - 2%) in nickel-based superalloys. These alloys are used in turbine vanes in the combustion zone of jet aircraft engines.
Nielsen RH; Hafnium and Hafnium Compounds. (2002) in Ullmann's Encycl Indust Chem. 7th ed. (2005). NY, NY: John Wiley & Sons. Online Posting Date: June 15, 2000.
The leading market for hafnium metal is as a addition in superalloys.
USGS; Mineral Commodity Summaries, Zirconium and Hafnium (2005). Available from, as of June 1, 2005: https://minerals.usgs.gov/minerals/pubs/mcs/

10.1.1 Use Classification

Hazard Classes and Categories -> Flammable - 3rd degree, Reactive - 3rd degree

10.1.2 Industry Uses

  • Other (specify)
  • Alloys

10.1.3 Consumer Uses

Other (specify)

10.2 Methods of Manufacturing

Extraction from the mineral cryolite.
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. 818
Prepared by thermal decomposition of its iodide; by reduction of tetrachloride or of hydrofluohafniate with metallic sodium; by reduction of oxide with a mixture of calcium and sodium.
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. 818
Extremely difficult to separate from zirconium. Most important methods are: 1) solvent extraction of thiocyanates by hexone; 2) solvent extraction of nitrates by tributyl phosphate; 3) fractional crystallization of double fluorides.
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 14th Edition. John Wiley & Sons, Inc. New York, NY 2001., p. 554
It was originally separated from zirconium by repeated recrystallization of the double ammonium or potassium fluorides by von Hevesey and Jantezen. Metallic hafnium was first prepared by van Arkel and deBoer by passing the vapor of the tetraiodide over heated a tungsten filament. Almost all hafnium metal now produced is made by reducing the tetrachloride with magnesium or with sodium (Kroll Process).
Lide, D.R. (ed.). CRC Handbook of Chemistry and Physics. 83rd ed. Boca Raton, Fl: CRC Press Inc., 2002-2003., p. 4-14
US 2741628
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. 818

10.3 Impurities

Of all elements, zirconium and hafnium are two of most difficult to separate. ... Very pure hafnium has been produced with zirconium being the major impurity.
Lide, DR (ed.). CRC Handbook of Chemistry and Physics. 71st ed. Boca Raton, FL: CRC Press Inc., 1990-1991., p. 4-15

10.4 Formulations / Preparations

Forms available: powder; rods; single crystals
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 14th Edition. John Wiley & Sons, Inc. New York, NY 2001., p. 554
Available in sponge, iodide crystal bar, ingot, wrought products from bar to foil, and wire
Kirk-Othmer Encyclopedia of Chemical Technology. 3rd ed., Volumes 1-26. New York, NY: John Wiley and Sons, 1978-1984., p. V12 72
Sold in chunk or particulate form /for alloying purposes/
Gerhartz, W. (exec ed.). Ullmann's Encyclopedia of Industrial Chemistry. 5th ed.Vol A1: Deerfield Beach, FL: VCH Publishers, 1985 to Present., p. VA12 564

10.5 Consumption Patterns

The largest use is as an alloy additive in nickel-based superalloys ... second major use is as a control-rod material in nuclear reactors
Gerhartz, W. (exec ed.). Ullmann's Encyclopedia of Industrial Chemistry. 5th ed.Vol A1: Deerfield Beach, FL: VCH Publishers, 1985 to Present., p. VA12: 564
YEARLY DEMAND FOR HAFNIUM IN US IS NOW IN EXCESS OF 60,000 LB.
Weast, R.C. (ed.). Handbook of Chemistry and Physics. 60th ed. Boca Raton, Florida: CRC Press Inc., 1979., p. B-11
The yearly demand for hafnium in the US is now /1990/ in excess of 100,000 lb
Lide, DR (ed.). CRC Handbook of Chemistry and Physics. 71st ed. Boca Raton, FL: CRC Press Inc., 1990-1991., p. 4-15
Yearly demand for hafnium in US is now /2002/ in excess of 50,000 kg.
Lide, DR (ed.). CRC Handbook of Chemistry and Physics. 81st Edition. CRC Press LLC, Boca Raton: FL 2000, p. 4-14

10.6 U.S. Production

Aggregated Product Volume

2019: <1,000,000 lb

2018: <1,000,000 lb

2017: <1,000,000 lb

2016: <1,000,000 lb

10.7 U.S. Imports

2 metric tons (1992; hafnium, unwrought and waste and scrap)
Bureau of Mines; 1992 Minerals Yearbook, Annual Report, US Dept Interior, p. 1494
(2000) 11 metric tons /Hafnium, unwrought, waste and scrap/
USGS; Mineral Commodity Summaries, Zirconium and Hafnium (2005). Available from, as of June 1, 2005: https://minerals.usgs.gov/minerals/pubs/mcs/
(2001) 5 metric tons /Hafnium, unwrought, waste and scrap/
USGS; Mineral Commodity Summaries, Zirconium and Hafnium (2005). Available from, as of June 1, 2005: https://minerals.usgs.gov/minerals/pubs/mcs/
(2002) 5 metric tons /Hafnium, unwrought, waste and scrap/
USGS; Mineral Commodity Summaries, Zirconium and Hafnium (2005). Available from, as of June 1, 2005: https://minerals.usgs.gov/minerals/pubs/mcs/
For more U.S. Imports (Complete) data for HAFNIUM, ELEMENTAL (6 total), please visit the HSDB record page.

10.8 General Manufacturing Information

Industry Processing Sectors
  • Petrochemical Manufacturing
  • Primary Metal Manufacturing
  • All Other Chemical Product and Preparation Manufacturing
  • Fabricated Metal Product Manufacturing
  • Computer and Electronic Product Manufacturing
  • Utilities
  • Transportation Equipment Manufacturing
EPA TSCA Commercial Activity Status
Hafnium: ACTIVE
Price of the metal is about $2/g.
Lide, D.R. (ed.). CRC Handbook of Chemistry and Physics. 83rd ed. Boca Raton, Fl: CRC Press Inc., 2002-2003., p. 4-14
...Extensively used as shielding material & as control rods in thermal nuclear reactors, because its thermal neutron cross section, 105 barns, is nearly 1000 times that of Zr; Hf can absorb & give up heat twice as fast as Zr & Ti. It is used as construction material in space technology & in jet engines...
Venugopal, B. and T.D. Luckey. Metal Toxicity in Mammals, 2. New York: Plenum Press, 1978., p. 203
Although hafnium /ore/ reserves are significant, demand is low and easily met as a byproduct of the production of reactor-grade zirconium
Gerhartz, W. (exec ed.). Ullmann's Encyclopedia of Industrial Chemistry. 5th ed.Vol A1: Deerfield Beach, FL: VCH Publishers, 1985 to Present., p. VA12 560
Six naturally occurring isotopes: 180 (35.22%); 178 (27.1%); 177 (18.56%); 179 (13.75%); 176 (5.21%); 174 (0.163%; alpha-emitter...); artificial isotopes: 157; 158; 168-173; 175; 181-183.
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. 818

11 Safety and Hazards

11.1 Hazards Identification

11.1.1 GHS Classification

1 of 2
View All
Note
Pictograms displayed are for 68.7% (233 of 339) of reports that indicate hazard statements. This chemical does not meet GHS hazard criteria for 31.3% (106 of 339) of reports.
Pictogram(s)
Flammable
Signal
Danger
GHS Hazard Statements
H250 (53.1%): Catches fire spontaneously if exposed to air [Danger Pyrophoric liquids]
Precautionary Statement Codes

P210, P222, P231, P233, P280, P302+P335+P334, and P370+P378

(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 339 reports by companies from 9 notifications to the ECHA C&L Inventory.

Reported as not meeting GHS hazard criteria per 106 of 339 reports by companies. For more detailed information, please visit ECHA C&L website.

There are 8 notifications provided by 233 of 339 reports by companies with hazard statement code(s).

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.

11.1.2 Hazard Classes and Categories

Pyr. Sol. 1 (53.1%)
Specific target organ toxicity - Repeated exposure - Hafnium and its compounds, Category 2 (liver)

11.1.3 Health Hazards

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

Fire will produce irritating, corrosive and/or toxic gases. Inhalation of decomposition products may cause severe injury or death. Contact with substance may cause severe burns to skin and eyes. Runoff from fire control or dilution water may cause environmental contamination. CAUTION: Pentaborane (UN1380) is highly toxic and may be fatal if inhaled, ingested or absorbed through skin. (ERG, 2024)

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

Oxides from metallic fires are a severe health hazard. Inhalation or contact with substance or decomposition products may cause severe injury or death. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may cause environmental contamination. (ERG, 2024)

ERG 2024, Guide 135 (Hafnium powder, dry)

· Fire will produce irritating, corrosive and/or toxic gases.

· Inhalation of decomposition products may cause severe injury or death.

· Contact with substance may cause severe burns to skin and eyes.

· Runoff from fire control or dilution water may cause environmental contamination.

CAUTION: Pentaborane (UN1380) is highly toxic and may be fatal if inhaled, ingested or absorbed through skin.

ERG 2024, Guide 170 (Hafnium powder, wetted with not less than 25% water)

· Oxides from metallic fires are a severe health hazard.

· Inhalation or contact with substance or decomposition products may cause severe injury or death.

· Fire may produce irritating, corrosive and/or toxic gases.

· Runoff from fire control or dilution water may cause environmental contamination.

11.1.4 Fire Hazards

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

Flammable/combustible material. May ignite on contact with moist air or moisture. May burn rapidly with flare-burning effect. Some react vigorously or explosively on contact with water. Some may decompose explosively when heated or involved in a fire. May re-ignite after fire is extinguished. Runoff may create fire or explosion hazard. Containers may explode when heated. (ERG, 2024)

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

May react violently or explosively on contact with water. Some are transported in flammable liquids. May be ignited by friction, heat, sparks or flames. Some of these materials will burn with intense heat. Dusts or fumes may form explosive mixtures in air. Containers may explode when heated. May re-ignite after fire is extinguished. (ERG, 2024)

ERG 2024, Guide 135 (Hafnium powder, dry)

· Flammable/combustible material.

· May ignite on contact with moist air or moisture.

· May burn rapidly with flare-burning effect.

· Some react vigorously or explosively on contact with water.

· Some may decompose explosively when heated or involved in a fire.

· May re-ignite after fire is extinguished.

· Runoff may create fire or explosion hazard.

· Containers may explode when heated.

ERG 2024, Guide 170 (Hafnium powder, wetted with not less than 25% water)

· May react violently or explosively on contact with water.

· Some are transported in flammable liquids.

· May be ignited by friction, heat, sparks or flames.

· Some of these materials will burn with intense heat.

· Dusts or fumes may form explosive mixtures in air.

· Containers may explode when heated.

· May re-ignite after fire is extinguished.

Flammable. Finely dispersed particles form explosive mixtures in air. Risk of fire and explosion. See Chemical Dangers.

11.1.5 Hazards Summary

The liver and lungs may be affected by heavy or prolonged exposures; [ICSC]

11.1.6 Fire Potential

The substance may spontaneously ignite on contact with air and at higher temperatures with nitrogen, phosphorous and sulphur. /Hafnium powder, wet or dry/
IPCS, CEC; International Chemical Safety Card on Hafnium. (October 1995). Available from, as of June 10, 2005: https://www.inchem.org/documents/icsc/icsc/eics0847.htm
Flammability: Both dry and wet may ignite in powders.
ITII. Toxic and Hazardous Industrial Chemicals Safety Manual. Tokyo, Japan: The International Technical Information Institute, 1988., p. 260

11.1.7 Skin, Eye, and Respiratory Irritations

Hafnium and its compounds are mild irritants of the eyes, skin, and mucous membranes. No industrial poisonings involving hafnium have been reported.
OSHA; Health Guidelines, NIOSH/OSHA/DOE for Hafnium (7440-58-6). Available from, as of July 13, 2005: https://www.osha.gov/SLTC/healthguidelines/hafnium/recognition.html#exposuresources
Irritant /to/ eyes.
Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. V2 p.725

11.2 Safety and Hazard Properties

11.2.1 Flammable Limits

Flammability
Explosive in powder form (either dry or with <25% water); finely divided powder can be ignited by static electricity or even SPONTANEOUSLY.

11.2.2 Physical Dangers

Ignites in air when finely divided. Dust explosion possible if in powder or granular form, mixed with air.

11.2.3 Explosive Limits and Potential

Explosive in powder form, either dry or wet with less than 25% water.
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 14th Edition. John Wiley & Sons, Inc. New York, NY 2001., p. 554

11.2.4 OSHA Standards

Permissible Exposure Limit: Table Z-1 8-hr Time Weighted Avg: 0.5 mg/cu m.
29 CFR 1910.1000 (7/1/98)

11.2.5 NIOSH Recommendations

Recommended Exposure Limit: 10 Hr Time-Weighted Avg: 0.5 mg/cu m.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997., p. 156

11.3 First Aid Measures

Inhalation First Aid
Fresh air, rest.
Skin First Aid
Rinse contaminated clothes (fire hazard) with plenty of water. Remove contaminated clothes. Rinse and then wash skin with water and soap.
Eye First Aid
Rinse with plenty of water (remove contact lenses if easily possible).
Ingestion First Aid
Rinse mouth.

11.3.1 First Aid

Excerpt from NIOSH Pocket Guide for Hafnium:

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: SOAP WASH PROMPTLY - If this chemical contacts the skin, promptly wash the contaminated skin with soap and water. If this chemical penetrates the clothing, promptly remove the clothing and wash the skin with soap and water. Get medical attention promptly.

Breathing: RESPIRATORY SUPPORT - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform artificial respiration. Keep the affected person warm and at rest. Get medical attention as soon as possible.

Swallow: MEDICAL ATTENTION IMMEDIATELY - If this chemical has been swallowed, get medical attention immediately. (NIOSH, 2024)

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

Refer to the "General First Aid" section. (ERG, 2024)

ERG 2024, Guide 135 (Hafnium powder, dry)

General First Aid:

· Call 911 or emergency medical service.

· Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.

· Move victim to fresh air if it can be done safely.

· Administer oxygen if breathing is difficult.

· If victim is not breathing:

-- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingestedor inhaled the substance.

-- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).

-- If no pulse detected or no respiratory medical device available, provide continuouscompressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.

· Remove and isolate contaminated clothing and shoes.

· For minor skin contact, avoid spreading material on unaffected skin.

· In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.

· For severe burns, immediate medical attention is required.

· Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed.

· Keep victim calm and warm.

· Keep victim under observation.

· For further assistance, contact your local Poison Control Center.

· Note: Basic Life Support (BLS) and Advanced Life Support (ALS) should be done by trained professionals.

In Canada, an Emergency Response Assistance Plan (ERAP) may be required for this product. Please consult the shipping paper and/or the "ERAP" section.

(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: Soap wash promptly - If this chemical contacts the skin, promptly wash the contaminated skin with soap and water. If this chemical penetrates the clothing, promptly remove the clothing and wash the skin with soap and water. Get medical attention promptly.

Breathing: Respiratory support

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

11.4 Fire Fighting

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

DO NOT USE WATER, CO2 OR FOAM ON MATERIAL ITSELF. Some of these materials may react violently with water. CAUTION: For Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite) UN1384, UN1923 and UN1929, USE FLOODING AMOUNTS OF WATER for SMALL AND LARGE fires to stop the reaction. Smothering will not work for these materials, they do not need air to burn.

SMALL FIRE: Dry chemical, soda ash, lime or DRY sand, EXCEPT for UN1384, UN1923, UN1929 and UN3342.

LARGE FIRE: DRY sand, dry chemical, soda ash or lime EXCEPT for UN1384, UN1923, UN1929 and UN3342, or withdraw from area and let fire burn. CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors. If it can be done safely, move undamaged containers away from the area around the fire.

FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers or in contact with substance. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. (ERG, 2024)

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

DO NOT USE WATER, FOAM OR CO2. Dousing metallic fires with water will generate hydrogen gas, an extremely dangerous explosion hazard, particularly if fire is in a confined environment (i.e., building, cargo hold, etc.). Use DRY sand, graphite powder, dry sodium chloride-based extinguishers, or class D extinguishers. Confining and smothering metal fires is preferable rather than applying water. If it can be done safely, move undamaged containers away from the area around the fire.

FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: If impossible to extinguish, protect surroundings and allow fire to burn itself out. (ERG, 2024)

Use special powder, dry sand, water in large amounts.

11.4.1 Fire Fighting Procedures

If material on fire or involved in fire: Use suitable dry powder. ... Use dry chemical or carbon dioxide. ... Use water only if flooding quantities are available. /Hafnium powder, dry/
Association of American Railroads/Bureau of Explosives; Emergency Handling of Hazardous Materials in Surface Transportation. Association of American Railroads. Pueblo, CO. 2002., p. 470
If material on fire or involved in fire: Use suitable dry powder. ... Use dry chemical or carbon dioxide. ... Use water only if flooding quantities are available. /Hafnium powder, wetted/
Association of American Railroads/Bureau of Explosives; Emergency Handling of Hazardous Materials in Surface Transportation. Association of American Railroads. Pueblo, CO. 2002., p. 470

11.5 Accidental Release Measures

Public Safety: ERG 2024, Guide 135 (Hafnium powder, dry)

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· Stay upwind, uphill and/or upstream.

· Keep unauthorized personnel away.

Spill or Leak: ERG 2024, Guide 135 (Hafnium powder, dry)

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

· Do not touch or walk through spilled material.

· Stop leak if you can do it without risk.

Small Spill

CAUTION: For spills of Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite), UN1384, UN1923 and UN1929, dissolve in 5 parts water and collect for proper disposal.

CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors.

· Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain.

· Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal.

· Prevent entry into waterways, sewers, basements or confined areas.

Spill or Leak: ERG 2024, Guide 170 (Hafnium powder, wetted with not less than 25% water)

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

· Do not touch or walk through spilled material.

· Stop leak if you can do it without risk.

· Prevent entry into waterways, sewers, basements or confined areas.

11.5.1 Isolation and Evacuation

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

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)

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

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.

LARGE SPILL: Consider initial downwind evacuation for at least 50 meters (160 feet).

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)

Evacuation: ERG 2024, Guide 135 (Hafnium powder, dry)

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

· For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.

· For non-highlighted materials: 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.

Evacuation: ERG 2024, Guide 170 (Hafnium powder, wetted with not less than 25% water)

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.

Large Spill

· Consider initial downwind evacuation for at least 50 meters (160 feet).

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.

11.5.2 Spillage Disposal

Remove all ignition sources. Evacuate danger area! Consult an expert! Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Wet powder to prevent dusting and ignition. Sweep spilled substance into covered water-filled containers. Then store and dispose of according to local regulations. Do NOT wash away into sewer. Do NOT absorb in saw-dust or other combustible absorbents.

11.5.3 Cleanup Methods

Persons not wearing protective equipment and clothing should be restricted from areas of spills until cleanup has been completed. 1. Ventilate area of spill. 2. Collect spilled material in most convenient and safe manner and deposit in sealed containers for reclamation, or for disposal in secured sanitary landfill. Liq containing hafnium...should be absorbed in vermiculite, dry sand, earth, or similar material.
Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) Publication No. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981.
Any spilled powder should be cleaned up immediately with water so that it has no chance to dry in place.
International Labour Office. Encyclopedia of Occupational Health and Safety. Volumes I and II. New York: McGraw-Hill Book Co., 1971., p. 1529
Spillage disposal: Evacuate danger area. Eliminate all sources of ignition. Do not wash away into sewer because it is flammable. Do not absorb in sawdust or other combustible absorbents. Wet the powder to prevent formation of dust or ignition; carefully collect the powder into sealable containers, and remove it to a safe place. During this procedure, use extra personal protection, e.g., a P2 filter respirator for harmful particles.
Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. V2 p.725
Environmental considerations: land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. ... Apply appropriate foam to diminish vapor and fire hazard. ... /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ /Hafnium powder, wetted/
Association of American Railroads/Bureau of Explosives; Emergency Handling of Hazardous Materials in Surface Transportation. Association of American Railroads. Pueblo, CO. 2002., p. 470
Environmental considerations: water spill: Use natural barriers or oil spill control booms to limit spill travel. /Hafnium powder, wetted/
Association of American Railroads/Bureau of Explosives; Emergency Handling of Hazardous Materials in Surface Transportation. Association of American Railroads. Pueblo, CO. 2002., p. 470

11.5.4 Disposal Methods

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.
If the quantity justifies recovery, get in touch with the supplier for special instructions.
ITII. Toxic and Hazardous Industrial Chemicals Safety Manual. Tokyo, Japan: The International Technical Information Institute, 1988., p. 260
Used papers and cloths which have become contaminated with powders should be kept wet in covered Containers until they are /disposed/.
International Labour Office. Encyclopedia of Occupational Health and Safety. Volumes I and II. New York: McGraw-Hill Book Co., 1971., p. 1529

11.5.5 Preventive Measures

Ventilation control: ...all processes using these materials /zirconium and hafnium/ should be...ventilated to keep air-borne contaminants far below.../5 mg/cu m/.
International Labour Office. Encyclopedia of Occupational Health and Safety. Volumes I and II. New York: McGraw-Hill Book Co., 1971., p. 1529
Care should be taken when machining metal or when handling hot sponge hafnium.
Weast, R.C. (ed.). Handbook of Chemistry and Physics. 60th ed. Boca Raton, Florida: CRC Press Inc., 1979., p. B-11
All sources of ignition, including static electric charges, should be eliminated from areas in which powder is to be handled. All surfaces...should be impervious and seamless so that they can be washed down with water and kept completely free from dust. Dried powders should be disturbed and handled as little as possible and then only with non-sparking tools.
International Labour Office. Encyclopedia of Occupational Health and Safety. Volumes I and II. New York: McGraw-Hill Book Co., 1971., p. 1529
The worker should immediately wash the skin when it becomes contaminated.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997., p. 156
For more Preventive Measures (Complete) data for HAFNIUM, ELEMENTAL (16 total), please visit the HSDB record page.

11.6 Handling and Storage

11.6.1 Nonfire Spill Response

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch or walk through spilled material. Stop leak if you can do it without risk.

SMALL SPILL: CAUTION: For spills of Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite), UN1384, UN1923 and UN1929, dissolve in 5 parts water and collect for proper disposal. CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors. Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal. Prevent entry into waterways, sewers, basements or confined areas. (ERG, 2024)

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. (ERG, 2024)

11.6.2 Safe Storage

Fireproof. Separated from strong oxidants, strong acids and halogens. Keep under inert gas. Store only in original container.

11.6.3 Storage Conditions

Storage: Store hafnium in a fireproof area. Keep it separate from strong oxidizing agents, strong bases, halogens, phosphorus, and sulfur. Keep stored under water.
Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. V2 p.725

11.7 Exposure Control and Personal Protection

Protective Clothing: ERG 2024, Guide 135 (Hafnium powder, dry)

· Wear positive pressure self-contained breathing apparatus (SCBA).

· Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE.

· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

Protective Clothing: ERG 2024, Guide 170 (Hafnium powder, wetted with not less than 25% water)

· Wear positive pressure self-contained breathing apparatus (SCBA).

· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

11.7.2 Permissible Exposure Limit (PEL)

0.5 [mg/m3], as Hf
PEL-TWA (8-Hour Time Weighted Average)
0.5 mg/m³
TWA 0.5 mg/m3 [*Note: The PEL also applies to other hafnium compounds (as Hf).]

11.7.3 Immediately Dangerous to Life or Health (IDLH)

50 mg Hf/m3 (NIOSH, 2024)

50.0 [mg/m3], as Hf

Excerpts from Documentation for IDLHs: No inhalation toxicity data are available on which to base an IDLH for hafnium compounds. Therefore, the revised IDLH for hafnium compounds is 50 mg Hf/m3 based on acute oral toxicity data in animals . . .

Recommended Exposure Limit: 50 mg/cu m (as Hf)
NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997., p. 156
50 mg/m³

50 mg/m3 (as Hf)

See: 7440586

11.7.4 Threshold Limit Values (TLV)

0.5 [mg/m3], as Hf
8 hr Time Weighted Avg (TWA): 0.5 mg/cu m. /Hafnium and compounds, as Hf/
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. 32
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. /Hafnium and compounds, as Hf/
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
0.5 mg/m
TLV-TWA (Time Weighted Average)
0.5 mg/m³ [1990]

11.7.5 Emergency Response Planning Guidelines

Emergency Response: ERG 2024, Guide 135 (Hafnium powder, dry)

· DO NOT USE WATER, CO2 OR FOAM ON MATERIAL ITSELF.

· Some of these materials may react violently with water.

CAUTION: For Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite) UN1384, UN1923 and UN1929, USE FLOODING AMOUNTS OF WATER for SMALL AND LARGE fires to stop the reaction. Smothering will not work for these materials, they do not need air to burn.

Small Fire

· Dry chemical, soda ash, lime or DRY sand, EXCEPT for UN1384, UN1923, UN1929 and UN3342.

Large Fire

· DRY sand, dry chemical, soda ash or lime EXCEPT for UN1384, UN1923, UN1929 and UN3342, or withdraw from area and let fire burn.

CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors.

· If it can be done safely, move undamaged containers away from the area around the fire.

Fire Involving Tanks, Rail Tank Cars or Highway Tanks

· Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles.

· Do not get water inside containers or in contact with substance.

· Cool containers with flooding quantities of water until well after fire is out.

· Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank.

· ALWAYS stay away from tanks in direct contact with flames.

Emergency Response: ERG 2024, Guide 170 (Hafnium powder, wetted with not less than 25% water)

· DO NOT USE WATER, FOAM OR CO2.

· Dousing metallic fires with water will generate hydrogen gas, an extremely dangerous explosion hazard, particularly if fire is in a confined environment (i.e., building, cargo hold, etc.).

· Use DRY sand, graphite powder, dry sodium chloride-based extinguishers, or class D extinguishers.

· Confining and smothering metal fires is preferable rather than applying water.

· If it can be done safely, move undamaged containers away from the area around the fire.

Fire Involving Tanks, Rail Tank Cars or Highway Tanks

· If impossible to extinguish, protect surroundings and allow fire to burn itself out.

11.7.6 Effects of Short Term Exposure

May cause mechanical irritation to the eyes, skin and respiratory tract.

11.7.7 Personal Protective Equipment (PPE)

Excerpt from NIOSH Pocket Guide for Hafnium:

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:

• WHEN CONTAMINATED - The worker should immediately wash the skin when it becomes contaminated.

• 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)

Excerpt from ERG Guide 170 [Metals (Powders, Dusts, Shavings, Borings, Turnings, or Cuttings, etc.)]:

Wear positive pressure self-contained breathing apparatus (SCBA). Structural firefighters' protective clothing provides thermal protection but only limited chemical protection. (ERG, 2024)

Workmen...should be meticulous in keeping powder off their clothing. If they wear rubber or plastic aprons, these should be treated with an anti-static compound.
International Labour Office. Encyclopedia of Occupational Health and Safety. Volumes I and II. New York: McGraw-Hill Book Co., 1971., p. 1529
Outer clothing made from synthetic fibers should be prohibited unless effectively treated with anti-static materials.
International Labour Office. Encyclopedia of Occupational Health and Safety. Volumes I and II. New York: McGraw-Hill Book Co., 1971., p. 1529
Wear appropriate personal protective clothing to prevent skin contact.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997., p. 156
Wear appropriate eye protection to prevent eye contact.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997., p. 156
For more Personal Protective Equipment (PPE) (Complete) data for HAFNIUM, ELEMENTAL (16 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: When contaminated/Daily

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

11.7.8 Respirator Recommendations

NIOSH/OSHA

Up to 2.5 mg/m3 :

(APF = 5) Any quarter-mask respirator.

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

Up to 5 mg/m3 :

(APF = 10) Any particulate respirator equipped with an N95, R95, or P95 filter (including N95, R95, and P95 filtering facepieces) except quarter-mask respirators. The following filters may also be used: N99, R99, P99, N100, R100, P100.

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

(APF = 10) Any supplied-air respirator

Up to 12.5 mg/m3 :

(APF = 25) Any supplied-air respirator operated in a continuous-flow mode*

(APF = 25) Any powered, air-purifying respirator with a high-efficiency particulate filter.*

Up to 25 mg/m3 :

(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter.

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

(APF = 50) Any supplied-air respirator that has a tight-fitting facepiece and is operated in a continuous-flow mode*

(APF = 50) Any powered, air-purifying respirator with a tight-fitting facepiece and a high-efficiency particulate filter*

(APF = 50) Any self-contained breathing apparatus with a full facepiece

(APF = 50) Any supplied-air respirator with a full facepiece

Up to 50 mg/m3 :

(APF = 2000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode

Emergency or planned entry into unknown concentrations or IDLH conditions:

(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 with 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

11.7.9 Preventions

Fire Prevention
NO open flames, NO sparks and NO smoking. Do NOT expose to friction or shock. Closed system, dust explosion-proof electrical equipment and lighting. Prevent deposition of dust.
Exposure Prevention
STRICT HYGIENE!
Inhalation Prevention
Avoid inhalation of dust. Use closed system.
Skin Prevention
Protective gloves.
Eye Prevention
Wear safety spectacles.
Ingestion Prevention
Do not eat, drink, or smoke during work. Wash hands before eating.

11.8 Stability and Reactivity

11.8.1 Air and Water Reactions

Highly flammable. The dry powder reacts with moisture to produce hydrogen, a flammable gas. The heat from this reaction may be sufficient to ignite the hydrogen. It does not appreciably react with large quantities of water.
Highly flammable. The dry powder is pyrophoric and readily ignitable by friction, heat or static electricity and burns fiercely. 5-10% water by mass slightly reduces the ease of ignition, but combustion of the damp powder proceeds explosively. A minimum of 25% water is necessary. Insoluble in water.

11.8.2 Reactive Group

Metals, Elemental and Powder, Active

Metals, Elemental and Powder, Active

Water and Aqueous Solutions

11.8.3 Reactivity Alerts

Strong Reducing Agent

Pyrophoric

Highly Flammable

Strong Reducing Agent

11.8.4 Reactivity Profile

Metals, such as HAFNIUM POWDER (reactivity similar to zirconium), are reducing agents and tend to react with oxidizing agents. Their reactivity is strongly influenced by their state of subdivision: in bulk they often resist chemical combination; in powdered form they may react very rapidly. Thus, as a bulk metal it is somewhat unreactive, but finely divided material may be pyrophoric. The metal reacts exothermically with compounds having active hydrogen atoms (such as acids and water) to form flammable hydrogen gas and caustic products. The reactions are less vigorous than the similar reactions of alkali metals, but the released heat can still ignite the released hydrogen. Materials in this group may react with azo/diazo compounds to form explosive products. These metals and the products of their corrosion by air and water can catalyze polymerization reactions in several classes of organic compounds; these polymerizations sometimes proceed rapidly or even explosively. Some metals in this group form explosive products with halogenated hydrocarbons.
Liable to spontaneous ignition. HAFNIUM POWDER is a reducing agent. Forms explosive mixtures with most oxidizing materials Reacts exothermically with compounds having active hydrogen atoms (such as acids and water) to form flammable hydrogen gas and caustic products. The reactions are less vigorous than the similar reactions of alkali metals, but the released heat can still ignite the released hydrogen. Materials in this group may react with azo/diazo compounds to form explosive products. These metals and the products of their corrosion by air and water can catalyze polymerization reactions in several classes of organic compounds; these polymerizations sometimes proceed rapidly or even explosively. Some metals in this group form explosive products with halogenated hydrocarbons. Can react explosively with oxidizing materials.

11.8.5 Hazardous Reactivities and Incompatibilities

Although /hafnium/ is relatively inert, when powdered it becomes very reactive. The dry powder may react explosively at elevated temperatures with nitrogen, phosphorus, oxygen, sulfur and other non-metals. The halogens react similarly, and in contact with hot concentrated nitric acid and other oxidants it may explode (often after a delay with nitric acid). The powder is pyrophoric and readily ignitable by friction, heat or static sparks, and if dry burns fiercely. Presence of water (5-10%) slightly reduces the ease of ignition, but combustion of the damp powder proceeds explosively (the oxygen content of water, 89%, being much higher than that of air).
Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990, p. 1270
Strong oxidizers, chlorine.
NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997., p. 156
Reacts violently with strong acids, strong oxidants, halogens causing explosion hazard. /Hafnium powder/
IPCS, CEC; International Chemical Safety Card on Hafnium. (October 1995). Available from, as of June 10, 2005: https://www.inchem.org/documents/icsc/icsc/eics0847.htm

11.9 Transport Information

11.9.1 DOT Emergency Guidelines

/GUIDE 135: SUBSTANCES - SPONTANEOUSLY COMBUSTIBLE/ Fire or Explosion: Flammable/combustible material. May ignite on contact with moist air or moisture. May burn rapidly with flare-burning effect. Some react vigorously or explosively on contact with water. Some may decompose explosively when heated or involved in a fire. May re-ignite after fire is extinguished. Runoff may create fire or explosion hazard. Containers may explode when heated. /Hafnium powder, dry/
U.S. Department of Transportation. 2004 Emergency Response Guidebook. A Guide book for First Responders During the Initial Phase of a Dangerous Goods/Hazardous Materials Incident. Washington, D.C. 2004
/GUIDE 135: SUBSTANCES - SPONTANEOUSLY COMBUSTIBLE/ Health: Fire will produce irritating, corrosive and/or toxic gases. Inhalation of decomposition products may cause severe injury or death. Contact with substance may cause severe burns to skin and eyes. Runoff from fire control may cause pollution. /Hafnium powder, dry/
U.S. Department of Transportation. 2004 Emergency Response Guidebook. A Guide book for First Responders During the Initial Phase of a Dangerous Goods/Hazardous Materials Incident. Washington, D.C. 2004
/GUIDE 135: SUBSTANCES - SPONTANEOUSLY COMBUSTIBLE/ Public Safety: CALL Emergency Response Telephone Number ... . As an 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. Stay upwind. Keep unauthorized personnel away. Keep out of low areas. /Hafnium powder, dry/
U.S. Department of Transportation. 2004 Emergency Response Guidebook. A Guide book for First Responders During the Initial Phase of a Dangerous Goods/Hazardous Materials Incident. Washington, D.C. 2004
/GUIDE 135: SUBSTANCES - SPONTANEOUSLY COMBUSTIBLE/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing will only provide limited protection. /Hafnium powder, dry/
U.S. Department of Transportation. 2004 Emergency Response Guidebook. A Guide book for First Responders During the Initial Phase of a Dangerous Goods/Hazardous Materials Incident. Washington, D.C. 2004
For more DOT Emergency Guidelines (Complete) data for HAFNIUM, ELEMENTAL (16 total), please visit the HSDB record page.

11.9.2 DOT ID and Guide

11.9.3 Shipping Name / Number DOT/UN/NA/IMO

UN 4237; Hafnium powder, dry
UN 2545; Hafnium powder, dry
UN 1326; Hafnium powder, wetted with not less than 25% water
IMO 4.2; Hafnium powder, dry
IMO 4.1; Hafnium powder, wetted with not less than 25% water

11.9.4 Standard Transportation Number

49 167 12; Hafnium metal, wet
49 167 11; Hafnium metal, dry

11.9.5 Shipment Methods and Regulations

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./
49 CFR 171.2; U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of February 5, 2004: https://www.ecfr.gov
The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.
IATA. Dangerous Goods Regulations. 45 th Ed. Montreal, Canada and Geneva, Switzerland. International Air Transport Association. Dangerous Goods Regulations, 2004., p. 177
The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.
IMDG; International Maritime Dangerous Goods Code; International Maritime Organization p.4237,4148 (1998)

11.9.6 DOT Label

Spontaneously Combustible
Flammable Solid

11.9.7 UN Classification

UN Hazard Class: 4.2; UN Pack Group: I

11.10 Regulatory Information

REACH Registered Substance

11.11 Other Safety Information

11.11.1 Toxic Combustion Products

Toxic gases and vapors ... may be released in a fire involving hafnium... .
Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) Publication No. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981.

11.11.2 Special Reports

USEPA; Development Document for Effluent Limitations, Guidelines, & Standards for the Nonferrous Metals Manufacturing Point Source Category. Vol 9 Primary & Secondary Titanium, Primary Zirconium & Hafnium; GRA & I Issue 11 (1990) EPA 440/1-89/019.9

12 Toxicity

12.1 Toxicological Information

12.1.1 Exposure Routes

inhalation, ingestion, skin and/or eye contact

12.1.2 Symptoms

Eye Exposure
Redness.
In Animals: irritation eyes, skin, mucous membrane; liver damage

12.1.3 Target Organs

Eyes, skin, mucous membrane, liver

12.1.4 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.

12.1.5 Medical Surveillance

Routine medical examinations should be provided to each employee who is exposed to hafnium and compounds at potentially hazardous levels. The employer should screen employees for history of liver disease. ... The importance of this organ in the biotransformation and detoxification of foreign substances should be considered before exposing persons with impaired liver function. Only those giving a positive history of these conditions should be referred for further medical examinations.
Mackison, F. W., R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health Guidelines for Chemical Hazards. DHHS(NIOSH) Publication No. 81-123 (3 VOLS). Washington, DC: U.S. Government Printing Office, Jan. 1981.

12.1.6 Human Toxicity Excerpts

/SIGNS AND SYMPTOMS/ Lungs may be affected by repeated or prolonged exposure. The substance may have effects on the liver.
IPCS, CEC; International Chemical Safety Card on Hafnium. (October 1995). Available from, as of June 10, 2005: https://www.inchem.org/documents/icsc/icsc/eics0847.htm
/SIGNS AND SYMPTOMS/ Overexposure to hafnium and its compounds may cause mild irritation of the eyes, skin, and mucous membranes.
OSHA; Health Guidelines, NIOSH/OSHA/DOE for Hafnium (7440-58-6). Available from, as of July 13, 2005: https://www.osha.gov/SLTC/healthguidelines/hafnium/recognition.html#exposuresources

12.1.7 Non-Human Toxicity Excerpts

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ To evaluate the biocompatibility of refractory metals, titanium, hafnium, niobium, tantalum and rhenium were implanted in rats, and histological observation and elemental mapping were performed by X-ray scanning analytical microscope (XSAM) and electron probe microanalyzer (EPMA). The titanium, hafnium, niobium, tantalum and rhenium wires were implanted in the subcutaneous tissue of the abdominal region and in femoral bone marrow of rats for either 2 or 4 weeks. No inflammatory response was observed around the implants, and all the implants were encapsulated with thin fibrous connective tissue. No dissolution of these metals was detected by XSAM in the soft tissue. Histological examination of the hard tissue showed that the amount of new bone formation decreased slightly from the second to the fourth week after implantation, and that the percentage of bone in contact with the implant increased markedly over the same period. No dissolution of these metals was detected by EPMA in the hard tissue. The Ca and P intensities in the mapping images of newly formed bone were higher after 4 weeks than those after 2 weeks, which suggests that the newly formed bone continued to mature from 2 to 4 weeks after implantation. These results indicate that titanium, hafnium, niobium, tantalum and rhenium have good biocompatibility and osteoconductivity.
Matsuno H et al; Biomaterials 22 (11): 1253-62 (2001)
/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ The aim of the present experimental study was to evaluate the tissue response to hafnium (Hf) a reactive metal closely related to titanium (Ti) and zirconium (Zr). Hf has not been previously evaluated as implant material in a biologic environment. In a first experiment, 21 machined Hf non-threaded implants (test) and 21 similar Ti implants (control) were inserted in the abdominal wall of 21 rats. Animals were sacrificed after 8 days (6 rats), 6 (7 rats) and 12 weeks (8 rats). In a second experiment, 18 rabbits received 18 Hf and 18 Ti threaded implants in their tibiae, one implant in each tibia. The rabbits were sacrificed after 6, 12 and 24 weeks (6 animals/time interval). The bulk metal of the abdominal wall implants, embedded together with the surrounding tissue, was electrolytically dissolved and semithin (1 microm) sections of the intact tissue-implant interface were evaluated by light microscopy (morphometry). Bone-implant contact and bone area within threads were evaluated in ground sections. In soft tissues, a fluid space containing predominantly monocytes/macrophages surrounded the abdominal implants at 8 days. At 6 and 12 weeks, a fibrous capsule, consisting of layers of macrophages and fibroblasts, surrounded the implants. Macrophages, including multinuclear giant cells, always formed the innermost layer in contact with the implant surface. No quantitative or qualitative difference in the tissue organization was detected between Ti and Hf implants. In rabbits, 6 weeks after insertion, the proximal two threads located within the cortical bone were filled with bone in contact with Hf and Ti. The distal threads contained bone marrow. After 12 and 24 weeks, mature bone was present in the proximal 3-4 implant threads. No statistically significant difference was found between Hf and Ti implants at any time periods. It is concluded that Hf is an interesting metal for biomedical applications in bone and soft tissue.
Mohammadi S et al; J Mater Sci Mater Med 12 (7): 603-11 (2001)
/OTHER TOXICITY INFORMATION/ There have been no published studies on the toxicity of metallic hafnium.
American Conference of Governmental Industrial Hygienists. Documentation of Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices for 2001. Cincinnati, OH. 2001., p. 1

12.2 Ecological Information

12.2.1 ICSC Environmental Data

Environmental effects from the substance have not been investigated adequately.

12.2.2 Natural Pollution Sources

Hafnium is...never found free in nature. It is always found associated with the more plentiful zirconium.
Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V12: 863 (1994)

13 Associated Disorders and Diseases

Associated Occupational Diseases with Exposure to the Compound
Pneumoconioses, benign [Category: Pneumoconiosis (Pulmonary Fibrosis)]

14 Literature

14.1 Consolidated References

14.2 NLM Curated PubMed Citations

14.3 Thieme References

14.4 Chemical Co-Occurrences in Literature

14.5 Chemical-Gene Co-Occurrences in Literature

14.6 Chemical-Disease Co-Occurrences in Literature

15 Patents

15.1 Depositor-Supplied Patent Identifiers

15.2 Chemical Co-Occurrences in Patents

15.3 Chemical-Disease Co-Occurrences in Patents

15.4 Chemical-Gene Co-Occurrences in Patents

16 Classification

16.1 MeSH Tree

16.2 NCI Thesaurus Tree

16.3 ChEBI Ontology

16.4 ChemIDplus

16.5 CAMEO Chemicals

16.6 UN GHS Classification

16.7 NORMAN Suspect List Exchange Classification

16.8 EPA DSSTox Classification

16.9 EPA TSCA and CDR Classification

16.10 EPA Substance Registry Services Tree

16.11 MolGenie Organic Chemistry Ontology

17 Information Sources

  1. CAMEO Chemicals
    LICENSE
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    https://cameochemicals.noaa.gov/help/reference/terms_and_conditions.htm?d_f=false
    HAFNIUM POWDER, WETTED WITH NOT LESS THAN 25% WATER
    https://cameochemicals.noaa.gov/chemical/3542
    CAMEO Chemical Reactivity Classification
    https://cameochemicals.noaa.gov/browse/react
  2. CAS Common Chemistry
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    https://creativecommons.org/licenses/by-nc/4.0/
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    https://pubchem.ncbi.nlm.nih.gov/source/ChemIDplus
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    https://www.epa.gov/web-policies-and-procedures/epa-disclaimers#copyright
  5. EPA Chemicals under the TSCA
    EPA TSCA Classification
    https://www.epa.gov/tsca-inventory
  6. EPA DSSTox
    CompTox Chemicals Dashboard Chemical Lists
    https://comptox.epa.gov/dashboard/chemical-lists/
  7. European Chemicals Agency (ECHA)
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    https://echa.europa.eu/web/guest/legal-notice
  8. FDA Global Substance Registration System (GSRS)
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    https://www.fda.gov/about-fda/about-website/website-policies#linking
  9. Hazardous Substances Data Bank (HSDB)
  10. ILO-WHO International Chemical Safety Cards (ICSCs)
  11. NJDOH RTK Hazardous Substance List
  12. Occupational Safety and Health Administration (OSHA)
    LICENSE
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    https://www.dol.gov/general/aboutdol/copyright
  13. Emergency Response Guidebook (ERG)
  14. The National Institute for Occupational Safety and Health (NIOSH)
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    https://www.cdc.gov/Other/disclaimer.html
  15. Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
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    https://haz-map.com/About
  16. Human Metabolome Database (HMDB)
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    http://www.hmdb.ca/citing
  17. ChEBI
  18. RRUFF Project
  19. Crystallography Open Database (COD)
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    https://creativecommons.org/publicdomain/zero/1.0/
  20. DailyMed
  21. NITE-CMC
  22. FooDB
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    https://foodb.ca/about
  23. Japan Chemical Substance Dictionary (Nikkaji)
  24. National Drug Code (NDC) Directory
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    https://www.fda.gov/about-fda/about-website/website-policies#linking
  25. NCI Thesaurus (NCIt)
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    https://www.cancer.gov/policies/copyright-reuse
  26. PubChem Elements
  27. USGS National Minerals Information Center
  28. SpringerMaterials
  29. Thieme Chemistry
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    https://creativecommons.org/licenses/by-nc-nd/4.0/
  30. Wikidata
  31. Wikipedia
  32. Medical Subject Headings (MeSH)
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    https://www.nlm.nih.gov/copyright.html
  33. PubChem
  34. GHS Classification (UNECE)
  35. NORMAN Suspect List Exchange
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    Data: CC-BY 4.0; Code (hosted by ECI, LCSB): Artistic-2.0
    https://creativecommons.org/licenses/by/4.0/
    NORMAN Suspect List Exchange Classification
    https://www.norman-network.com/nds/SLE/
  36. EPA Substance Registry Services
  37. MolGenie
    MolGenie Organic Chemistry Ontology
    https://github.com/MolGenie/ontology/
  38. NCBI
CONTENTS