An official website of the United States government

Hydrogen

PubChem CID
783
Structure
Hydrogen_small.png
Molecular Formula
Synonyms
  • Hydrogen
  • 1333-74-0
  • H
  • Molecular hydrogen
  • Dihydrogen
Molecular Weight
2.016 g/mol
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Element Name
Dates
  • Create:
    2004-09-16
  • Modify:
    2025-01-18
Description
Hydrogen is a colorless, odorless gas. It is easily ignited. Once ignited it burns with a pale blue, almost invisible flame. The vapors are lighter than air. It is flammable over a wide range of vapor/air concentrations. Hydrogen is not toxic but is a simple asphyxiate by the displacement of oxygen in the air. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket. Hydrogen is used to make other chemicals and in oxyhydrogen welding and cutting.
Hydrogen, refrigerated liquid (cryogenic liquid) appears as a colorless very cold liquid shipped in special heavily insulated containers. Boils at -442 °F. Contact causes severe frostbite. Hydrogen gas at normal temperatures is lighter than air but until vapors boiling off from the liquid warm up they are heavier than air. Very easily ignited. Burns with a pale blue, almost invisible flame. A leak could be either a vapor or a liquid leak. The container is designed to vent the vapor as it is boils off. Under prolonged exposure to intense heat the containers may rupture violently and rocket.
Dihydrogen is an elemental molecule consisting of two hydrogens joined by a single bond. It has a role as an antioxidant, an electron donor, a fuel, a human metabolite and a member of food packaging gas. It is an elemental hydrogen, a gas molecular entity and an elemental molecule.

1 Structures

1.1 2D Structure

Chemical Structure Depiction
Hydrogen.png

2 Names and Identifiers

2.1 Computed Descriptors

2.1.1 IUPAC Name

molecular hydrogen
Computed by Lexichem TK 2.7.0 (PubChem release 2021.10.14)

2.1.2 InChI

InChI=1S/H2/h1H
Computed by InChI 1.0.6 (PubChem release 2021.10.14)

2.1.3 InChIKey

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

2.1.4 SMILES

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

2.2 Molecular Formula

H2
Computed by PubChem 2.2 (PubChem release 2021.10.14)
H2

2.3 Other Identifiers

2.3.1 CAS

1333-74-0

2.3.2 Deprecated CAS

725200-57-7

2.3.3 European Community (EC) Number

215-605-7

2.3.4 UNII

2.3.5 UN Number

2.3.6 ChEBI ID

2.3.7 DrugBank 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 NSC Number

2.3.13 Wikidata

2.3.14 Wikipedia

2.4 Synonyms

2.4.1 MeSH Entry Terms

  • Hydrogen
  • Hydrogen-1
  • Protium

2.4.2 Depositor-Supplied Synonyms

3 Chemical and Physical Properties

3.1 Computed Properties

Property Name
Molecular Weight
Property Value
2.016 g/mol
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
XLogP3-AA
Property Value
0
Reference
Computed by XLogP3 3.0 (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
2.0156500638 Da
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
Monoisotopic Mass
Property Value
2.0156500638 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
0
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

Hydrogen is a colorless, odorless gas. It is easily ignited. Once ignited it burns with a pale blue, almost invisible flame. The vapors are lighter than air. It is flammable over a wide range of vapor/air concentrations. Hydrogen is not toxic but is a simple asphyxiate by the displacement of oxygen in the air. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket. Hydrogen is used to make other chemicals and in oxyhydrogen welding and cutting.
Hydrogen, refrigerated liquid (cryogenic liquid) appears as a colorless very cold liquid shipped in special heavily insulated containers. Boils at -442 °F. Contact causes severe frostbite. Hydrogen gas at normal temperatures is lighter than air but until vapors boiling off from the liquid warm up they are heavier than air. Very easily ignited. Burns with a pale blue, almost invisible flame. A leak could be either a vapor or a liquid leak. The container is designed to vent the vapor as it is boils off. Under prolonged exposure to intense heat the containers may rupture violently and rocket.
Gas or Vapor; Dry Powder, Water or Solvent Wet Solid; Liquid; Gas or Vapor, Liquid
Colourless, odourless, highly flammable gas
Colorless gas; [HSDB] Vapor density = 0.069 (lighter than air); [HSDB]
Liquid
ODOURLESS COLOURLESS COMPRESSED GAS.

3.2.2 Color / Form

Colorless gas
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-66
... hydrogen under ordinary conditions consists of two kinds of molecules, known as ortho- and para-hydrogen, which differ from one another by the spins of their electrons and nuclei. Normal hydrogen at room temperature contains 25% of the para form and 75% of the ortho form. The ortho form cannot be prepared in the pure state
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-17

3.2.3 Odor

Odorless
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. V4: 22431

3.2.4 Taste

Tasteless
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. V4: 2431

3.2.5 Boiling Point

-423 °F at 760 mmHg (USCG, 1999)
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
-259.16 °C
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-66
-253 °C

3.2.6 Melting Point

-434 °F (USCG, 1999)
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
-252.762 °C
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-66
-259.2 °C
-259 °C

3.2.7 Flash Point

Flammable gas

3.2.8 Solubility

In water, 1.62 mg/L at 21 °C
Venable CS, Fuwa T; Ind Eng Chem 14: 139-42 (1922)
Soluble in about 50 volumes of water at 0 degC
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 887
Very low solubility in most liquids
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. V4: 2431
0.00162 mg/mL at 21 °C
Solubility in water, mg/l at 21 °C: 1.62 (very poor)

3.2.9 Density

0.071 at -423.4 °F (USCG, 1999) - Less dense than water; will float
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
0.082 g/L
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-66
Density: 0.069 (gas) (Air= 1); 0.0700 at BP (liq); 0.0763 at 13 K (solid). One liter of gas at 0 °C weighs 0.08987 g
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 887
Physical and Thermodynmic Properties Gaseous Hydrogen
Baade WF et al; Hydrogen. Kirk-Othmer Encyclopedia of Chemical Technology. (1999-2017). New York, NY: John Wiley & Sons. Online Posting Date: 20 Dec 2001
Physical and Thermodynamic Properties of Solid Hydrogen
Baade WF et al; Hydrogen. Kirk-Othmer Encyclopedia of Chemical Technology. (1999-2017). New York, NY: John Wiley & Sons. Online Posting Date: 20 Dec 2001

3.2.10 Vapor Density

Relative vapor density (air = 1): 0.07

3.2.11 Vapor Pressure

1.24X10+6 mm Hg at 25 °C
Ohe S; Computer Aided Data Book of Vapor Pressure. Data Book Publ. Co, Tokyo, Japan (1976)
Vapor pressure, kPa at 25 °C: 165320

3.2.12 Stability / Shelf Life

Stable under recommended storage conditions.
Sigma-Aldrich; Safety Data Sheet for Hydrogen. Product Number: , Version 3.10 (Revision Date 05/27/2016). Available from, as of June 16, 2017: https://www.sigmaaldrich.com/safety-center.html

3.2.13 Autoignition Temperature

1065 °F (USCG, 1999)
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
932 °F (500 °C)
National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-72
560 °C

3.2.14 Corrosivity

Noncorrosive
Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 733

3.2.15 Heat of Combustion

-285.8 kJ/mol
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 5-68

3.2.16 Heat of Vaporization

0.90 kJ/mol at -252.87 °C
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 6-129

3.2.17 Other Experimental Properties

Atomic number 1; valence 1; elemental state: H2; isotopes: (1)H (protium 99.9844%), (2)H (deuterium 0.0156%), (3)H (tritium, traces only)
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 887
MP: -259.2 deg (13.96 K) at 54 mm (triple point); BP: -252.77 (20.39 K)
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 887
Ionization potential of H atom is 13.59 electron volts; 1 L of gas at 0 °C weighs 0.08987 g
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 887
Lightest of all gases; lifting power of 1 cu ft hydrogen gas is about 0.076 lb at 0 °C, 760 mm Hg
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-17
... Hydrogen gas under ordinary conditions is a mix of 2 kinds of molecules, known as ortho- & para-hydrogen, which differ from one another by the spins of their electrons & nuclei. Normal hydrogen at room temp contains 25% of para form & 75% ortho form. The ortho form cannot be prepd in the pure state.
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 94th Edition. CRC Press LLC, Boca Raton: FL 2013-2014, p. 4-18
In 1973, it was reported that a group of Russian experimenters may have produced metallic hydrogen at a pressure of 2.8 Mbar... earlier, in 1972, a Livermore (California) group also reported on a similar experiment in which they observed a pressure-volume point centered at 2 Mbar. It has been predicted that metallic hydrogen may be metastable; others have predicted it would be a superconductor at room temperature.
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 94th Edition. CRC Press LLC, Boca Raton: FL 2013-2014, p. 4-17
For more Other Experimental Properties (Complete) data for Hydrogen (15 total), please visit the HSDB record page.

3.3 SpringerMaterials Properties

3.4 Chemical Classes

Toxic Gases & Vapors -> Simple Asphyxiants

4 Spectral Information

4.1 Mass Spectrometry

4.1.1 GC-MS

1 of 3
View All
NIST Number
245692
Library
Main library
Total Peaks
2
m/z Top Peak
2
m/z 2nd Highest
1
m/z 3rd Highest
0
Thumbnail
Thumbnail
2 of 3
View All
Source of Spectrum
Chemical Concepts, A Wiley Division, Weinheim, Germany
Copyright
Copyright © 2002-2024 Wiley-VCH Verlag GmbH & Co. KGaA. All Rights Reserved.
Thumbnail
Thumbnail

6 Chemical Vendors

7 Drug and Medication Information

7.1 FDA National Drug Code Directory

7.2 Clinical Trials

7.2.1 ClinicalTrials.gov

7.2.2 NIPH Clinical Trials Search of Japan

7.3 Therapeutic Uses

/EXPL THER/ Hydrogen-rich saline (HRS) is a novel protection against various oxidative disorders and almost all types of inflammation. Moreover, its toxicity and side effects are rarely reported. We sought to clarify the protective effect of HRS against the oxygen-induced retinopathy (OIR) in C57BL/6 J model. The OIR in the HRS treated mice and the untreated controls were systematically compared. The retinas of both groups were analyzed using high-molecular-weight FITC-dextran staining of flat-mount preparations, hematoxylin and eosin (H&E) staining of cross-sections. The distribution and expression of the vascular endothelial growth factor (VEGF) were also evaluated by the immunohistochemical measurements between postnatal days 17 (P17) and P21. The leakage and non-perfusion areas of retinal blood vessels were not alleviated in the HRS treatment group. Moreover, the number of preretinal vascular endothelial cell in the HRS treatment group was similar to that in the untreated group after exposure to hyperoxia (P>0.05). The degree of OIR was positively correlated with the expression level of VEGF. Intriguingly, the preretinal vascular endothelial cell count in the retinas of pups reared in room air with HRS treatment was 15.21+/-2.98. The preretinal vascular endothelial cell count of the HRS treated mice was significantly higher than that of the untreated group reared in room air. In summary, HRS therapy (at the dose of 10mL/day, applied between P12 and P17) did not inhibit retinal neovascularization in OIR; On the contrary, it would induce the retinal neovascularization during the development of normal retinas. /Hydrogen-rich saline/
Zhang Q et al; Life Sci 153: 17-22 (2016)
/EXPL THER/ Acute pancreatitis (AP) is an inflammatory disease mediated by damage to acinar cells and pancreatic inflammation. In patients with AP, subsequent systemic inflammatory responses and multiple organs dysfunction commonly occur. Interactions between cytokines and oxidative stress greatly contribute to the amplification of uncontrolled inflammatory responses. Molecular hydrogen (H2) is a potent free radical scavenger that not only ameliorates oxidative stress but also lowers cytokine levels. The aim of the present study was to investigate the protective effects of H2 gas on AP both in vitro and in vivo. For the in vitro assessment, AR42J cells were treated with cerulein and then incubated in H2-rich or normal medium for 24 hr, and for the in vivo experiment, AP was induced through a retrograde infusion of 5% sodium taurocholate into the pancreatobiliary duct (0.1 mL/100 g body weight). Wistar rats were treated with inhaled air or 2% H2 gas and sacrificed 12 hr following the induction of pancreatitis. Specimens were collected and processed to measure the amylase and lipase activity levels; the myeloperoxidase activity and production levels; the cytokine mRNA expression levels; the 8-hydroxydeoxyguanosine, malondialdehyde, and glutathione levels; and the cell survival rate. Histological examinations and immunohistochemical analyses were then conducted. The results revealed significant reductions in inflammation and oxidative stress both in vitro and in vivo. Furthermore, the beneficial effects of H2 gas were associated with reductions in AR42J cell and pancreatic tissue damage. In conclusion, our results suggest that H2 gas is capable of ameliorating damage to the pancreas and AR42J cells and that H2 exerts protective effects both in vitro and in vivo on subjects with AP. Thus, the results obtained indicate that this gas may represent a novel therapy agent in the management of AP.
Zhou HX et al; PLoS One 11 (4): e0154483 (2016)
/EXPL THER/ Hydrogen gas inhalation (HI) ameliorates cerebral and cardiac dysfunction in animal models of post-cardiac arrest syndrome (PCAS). HI for human patients with PCAS has never been studied. Between January 2014 and January 2015, 21 of 107 patients with out-of-hospital cardiac arrest achieved spontaneous return of circulation. After excluding 16 patients with specific criteria, 5 patients underwent HI together with target temperature management (TTM). No undesirable effects attributable to HI were observed and 4 patients survived 90 days with a favorable neurological outcome. HI in combination with TTM is a feasible therapy for patients with PCAS.
Tamura T et al; Circ J. 80 (8): 1870-3 (2016)
/EXPL THER/ Premature ovarian failure (POF) is a disease that affects female fertility but has few effective treatments. Ovarian reserve function plays an important role in female fertility. Recent studies have reported that hydrogen can protect male fertility. Therefore, we explored the potential protective effect of hydrogen-rich water on ovarian reserve function through a mouse immune POF model. To set up immune POF model, fifty female BALB/c mice were randomly divided into four groups: Control (mice consumed normal water, n = 10), hydrogen (mice consumed hydrogen-rich water, n = 10), model (mice were immunized with zona pellucida glycoprotein 3 [ZP3] and consumed normal water, n = 15), and model-hydrogen (mice were immunized with ZP3 and consumed hydrogen-rich water, n = 15) groups. After 5 weeks, mice were sacrificed. Serum anti-Mullerian hormone (AMH) levels, granulosa cell (GC) apoptotic index (AI), B-cell leukemia/lymphoma 2 (Bcl-2), and BCL2-associated X protein (Bax) expression were examined. Analyses were performed using SPSS 17.0 (SPSS Inc., Chicago, IL, USA) software. Immune POF model, model group exhibited markedly reduced serum AMH levels compared with those of the control group (5.41 +/- 0.91 ng/ml vs. 16.23 +/- 1.97 ng/mL, P = 0.033) and the hydrogen group (19.65 +/- 7.82 ng/mL, P = 0.006). The model-hydrogen group displayed significantly higher AMH concentrations compared with that of the model group (15.03 +/- 2.75 ng/mL vs. 5.41 +/- 0.91 ng/mL, P = 0.021). The GC AI was significantly higher in the model group (21.30 +/- 1.74%) than those in the control (7.06 +/- 0.27%), hydrogen (5.17 +/- 0.41%), and model-hydrogen groups (11.24 +/- 0.58%) (all P < 0.001). The GC AI was significantly higher in the model-hydrogen group compared with that of the hydrogen group (11.24 +/- 0.58% vs. 5.17 +/- 0.41%, P = 0.021). Compared with those of the model group, ovarian tissue Bcl-2 levels increased (2.18 +/- 0.30 vs. 3.01 +/- 0.33, P = 0.045) and the Bax/Bcl-2 ratio decreased in the model-hydrogen group. Hydrogen-rich water may improve serum AMH levels and reduce ovarian GC apoptosis in a mouse immune POF model induced by ZP3. /Hydrogen-rich water/
He X et al; Chin Med J (Engl) 129 (19): 2331-7 (2016)
For more Therapeutic Uses (Complete) data for Hydrogen (24 total), please visit the HSDB record page.

8 Food Additives and Ingredients

8.1 Associated Foods

9 Minerals

10 Pharmacology and Biochemistry

10.1 Absorption, Distribution and Excretion

Molecular hydrogen (H2) is an agent with potential applications in oxidative stress-related and/or inflammatory disorders. H2 is usually administered by inhaling H2-containing air (HCA) or by oral intake of H2-rich water (HRW). Despite mounting evidence, the molecular mechanism underlying the therapeutic effects and the optimal method of H2 administration remain unclear. Here, we investigated whether H2 affects signaling pathways and gene expression in a dosage- or dose regimen-dependent manner. We first examined the H2 concentrations in blood and organs after its administration and found that oral intake of HRW rapidly but transiently increased H2 concentrations in the liver and atrial blood, while H2 concentrations in arterial blood and the kidney were one-tenth of those in the liver and atrial blood. In contrast, inhalation of HCA increased H2 equally in both atrial and arterial blood ...
Sobue S et al; Mol Cell Biochem 403 (1-2): 231-41 (2015)
Hydrogen exerts beneficial effects in disease animal models of ischemia-reperfusion injury as well as inflammatory and neurological disease. Additionally, molecular hydrogen is useful for various novel medical and therapeutic applications in the clinical setting. In the present study, the hydrogen concentration in rat blood and tissue was estimated. Wistar rats were orally administered hydrogen super-rich water (HSRW), intraperitoneal and intravenous administration of hydrogen super-rich saline (HSRS), and inhalation of hydrogen gas. A new method for determining the hydrogen concentration was then applied using ... sensor gas chromatography, after which the specimen was prepared via tissue homogenization in airtight tubes. This method allowed for the sensitive and stable determination of the hydrogen concentration. The hydrogen concentration reached a peak at 5 minutes after oral and intraperitoneal administration, compared to 1 minute after intravenous administration. Following inhalation of hydrogen gas, the hydrogen concentration was found to be significantly increased at 30 minutes and maintained the same level thereafter. These results demonstrate that accurately determining the hydrogen concentration in rat blood and organ tissue is very useful and important for the application of various novel medical and therapeutic therapies using molecular hydrogen. /Hydrogen super-rich water or saline/
Liu C et al; Sci Rep 4: 5485 (2014)

10.2 Metabolism / Metabolites

The ability of mammalian tissues to oxidize hydrogen under conditions similar to those encountered by deep divers breathing mixtures containing hydrogen was investigated. The kidneys, livers, spleen, heart, lungs, and quadriceps muscle were removed from guinea-pigs and rats. After mincing or homogenization, the tissues, along with myocytes prepared from rat hearts and porcine cerebral cortex capillary endothelial cells were placed in petri dishes and exposed to tritium tagged hydrogen at a pressure of 1 or 5 megapascals (MPa) for 1 hour in a specially designed exposure system. Helium at a pressure of 1 MPa was used as a carrier. Petri dishes filled with distilled water or saline served as negative controls. After decompression, the extent of hydrogen oxidized by the mammalian tissues and cells was determined by measuring the amounts of incorporated tritium by liquid scintillation counting. The tissues and cells incorporated tritium only at the rate of 10 to 50 nanomoles per gram per minute (nmol/g/min), rates that were similar to those of the negative controls. The authors conclude that mammalian tissues do not oxidize hydrogen under hyperbaric conditions. The small amounts of tritium label incorporation observed in the tissues is probably due to radioisotope phenomena, which sets the detection limit for determining hydrogen oxidation at 100 nmol/g/min.
Kayar SR et al; Undersea and Hyperbaric Medicine 21 (3): 265-275 (1994)

10.3 Mechanism of Action

Substantial evidence indicates that molecular hydrogen (H2) has beneficial vascular effects because of its antioxidant and/or anti-inflammatory effects. Thus, hydrogen-rich water may prove to be an effective anti-aging drink. This study examined the effects of H2 on endothelial senescence and clarified the mechanisms involved. Hydrogen-rich medium was produced by a high-purity hydrogen gas generator. Human umbilical vein endothelial cells (HUVECs) were incubated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for various time periods in normal or hydrogen-rich medium. The baseline H2concentration in hydrogen-rich medium was 0.55 +/- 0.07 mmol/L. This concentration gradually decreased, and H2 was almost undetectable in medium after 12 hr. At 24 hr after TCDD exposure, HUVECs treated with TCDD exhibited increased 8OHdG and acetyl-p53 expression, decreased nicotinamide adenine dinucleotide (NAD(+))/NADH ratio, impaired Sirt1 activity, and enhanced senescence-associated beta-galactosidase. However, HUVECs incubated in hydrogen-rich medium did not exhibit these TCDD-induced changes accompanying Nrf2 activation, which was observed even after H2 was undetectable in the medium. Chrysin, an inhibitor of Nrf2, abolished the protective effects of H2 on HUVECs. H2 has long-lasting antioxidant and anti-aging effects on vascular endothelial cells through the Nrf2 pathway, even after transient exposure to H2. Hydrogen-rich water may thus be a functional drink that increases longevity. /Hydrogen-rich water/
Hara F et al; Circ J 80 (9): 2037-46 (2016)
Amyloid beta (Abeta) peptides are identified /as a/ cause of neurodegenerative diseases such as Alzheimer's disease (AD). Previous evidence suggests Abeta-induced neurotoxicity is linked to the stimulation of reactive oxygen species (ROS) production. The accumulation of Abeta-induced ROS leads to increased mitochondrial dysfunction and triggers apoptotic cell death. This suggests antioxidant therapies may be beneficial for preventing ROS-related diseases such as AD. Recently, hydrogen-rich water (HRW) has been proven effective in treating oxidative stress-induced disorders because of its ROS-scavenging abilities. However, the precise molecular mechanisms whereby HRW prevents neuronal death are still unclear. In the present study, we evaluated the putative pathways by which HRW protects against Abeta-induced cytotoxicity /in SK-N-MC cells/. Our results indicated that HRW directly counteracts oxidative damage by neutralizing excessive ROS, leading to the alleviation of Abeta-induced cell death. In addition, HRW also stimulated AMP-activated protein kinase (AMPK) in a sirtuin 1 (Sirt1)-dependent pathway, which upregulates forkhead box protein O3a (FoxO3a) downstream antioxidant response and diminishes Abeta-induced mitochondrial potential loss and oxidative stress. Taken together, our findings suggest that HRW may have potential therapeutic value to inhibit Abeta-induced neurotoxicity. /Hydrogen-rich water/
Lin CL et al; Chem Biol Interact 240: 12-21 (2015)
The NLRP3 inflammasome, an intracellular multi-protein complex controlling the maturation of cytokine interleukin-1beta, plays an important role in lipopolysaccharide (LPS)-induced inflammatory cascades. Recently, the production of mitochondrial reactive oxygen species (mtROS) in macrophages stimulated with LPS has been suggested to act as a trigger during the process of NLRP3 inflammasome activation that can be blocked by some mitochondria-targeted antioxidants. Known as a ROS scavenger, molecular hydrogen (H2) has been shown to possess therapeutic benefit on LPS-induced inflammatory damage in many animal experiments. Due to the unique molecular structure, H2 can easily target the mitochondria, suggesting that H2 is a potential antagonist of mtROS-dependent NLRP3 inflammasome activation. Here we have showed that, in mouse macrophages, H2 exhibited substantial inhibitory activity against LPS-initiated NLRP3 inflammasome activation by scavenging mtROS. Moreover, the elimination of mtROS by H2 resultantly inhibited mtROS-mediated NLRP3 deubiquitination, a non-transcriptional priming signal of NLRP3 in response to the stimulation of LPS. Additionally, the removal of mtROS by H2 reduced the generation of oxidized mitochondrial DNA and consequently decreased its binding to NLRP3, thereby inhibiting the NLRP3 inflammasome activation. Our findings have, for the first time, revealed the novel mechanism underlying the inhibitory effect of molecular hydrogen on LPS-caused NLRP3 inflammasome activation, highlighting the promising application of this new antioxidant in the treatment of LPS-associated inflammatory pathological damage.
Ren JD et al; Biochim Biophys Acta 1863 (1): 50-5 (2016)
... H2 decreased the tyrosine nitration level and suppressed oxidative stress damage in retinal cells. S-nitroso-N-acetylpenicillamine treatment decreased the cell numbers in the ganglion cell layer and inner nuclear layer, but the presence of H2 inhibited this reduction. These findings suggest that H2 has a neuroprotective effect against retinal cell oxidative damage, presumably by scavenging peroxynitrite. H2 reduces cellular peroxynitrite, a highly toxic reactive nitrogen species. Thus, H2 may be an effective and novel clinical tool for treating glaucoma and other oxidative stress-related diseases.
Yokota T et al; Clin Exp Ophthalmol 43 (6): 568-77 (2015)
Endothelial injury is a primary cause of sepsis and sepsis-induced organ damage. Heme oxygenase-1 (HO-1) plays an essential role in endothelial cellular defenses against inflammation by activating nuclear factor E2-related factor-2 (Nrf2). We found that molecular hydrogen (H2) exerts an anti-inflammatory effect. Here, we hypothesized that H2 attenuates endothelial injury and inflammation via an Nrf2-mediated HO-1 pathway during sepsis. First, we detected the effects of H2 on cell viability and cell apoptosis in human umbilical vein endothelial cells (HUVECs) stimulated by LPS. Then, we measured cell adhesion molecules and inflammatory factors in HUVECs stimulated by LPS and in a cecal ligation and puncture (CLP)-induced sepsis mouse model. Next, the role of Nrf2/HO-1 was investigated in activated HUVECs, as well as in wild-type and Nrf(-/-) mice with sepsis. We found that both 0.3 mmol/L and 0.6 mmol/L (i.e., saturated) H2-rich media improved cell viability and cell apoptosis in LPS-activated HUVECs and that 0.6 mmol/L (i.e., saturated) H2-rich medium exerted an optimal effect. H2 could suppress the release of cell adhesion molecules, such as vascular cell adhesion molecule-1 (VCAM-1) and intercellular cell adhesion molecule-1 (ICAM-1), and pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-a, interleukin (IL)-1beta and high-mobility group box 1 protein (HMGB1). Furthermore, H2 could elevate anti-inflammatory cytokine IL-10 levels in LPS-stimulated HUVECs and in lung tissue from CLP mice. H2 enhanced HO-1 expression and activity in vitro and in vivo. HO-1 inhibition reversed the regulatory effects of H2 on cell adhesion molecules and inflammatory factors. H2 regulated endothelial injury and the inflammatory response via Nrf2-mediated HO-1 levels. These results suggest that H2 could suppress excessive inflammatory responses and endothelial injury via an Nrf2/HO-1 pathway. /Hydrogen-rich media/
Chen H et al; Int Immunopharmacol 28 (1): 643-54 (2015)

10.4 Human Metabolite Information

10.4.1 Cellular Locations

  • Cytoplasm
  • Endoplasmic reticulum
  • Extracellular
  • Golgi apparatus
  • Lysosome
  • Mitochondria
  • Nucleus
  • Peroxisome

10.4.2 Metabolite Pathways

10.5 Biochemical Reactions

11 Use and Manufacturing

11.1 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 in welding (oxy-hydrogen and autogenous), petroleum refining, and as a coolant; Used to hydrogenate oils and other organic compounds and to reduce metal oxides; [Merck Index]
Merck Index - O'Neil MJ, Heckelman PE, Dobbelaar PH, Roman KJ (eds). The Merck Index, An Encyclopedia of Chemicals, Drugs, and Biologicals, 15th Ed. Cambridge, UK: The Royal Society of Chemistry, 2013.
Industrial Processes with risk of exposure

Petroleum Production and Refining [Category: Industry]

Gas Welding and Cutting [Category: Weld]

In oxy-hydrogen blowpipe (welding) and limelight; autogenous welding of steel and other metals; manufacturing ammonia, synthetic methanol, HCl, NH3; hydrogenation of oils, fats, naphthalene, phenol; in balloons and airships; in metallurgy to reduce oxides to metals; in petroleum refining; in thermonuclear reactions (ionizes to form protons, deuterons (D) or tritons (T).
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 887
In bubble chambers to study subatomic particles; as a coolant. /Liquid hydrogen/
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 887
In cryogenics; in study of superconductivity /Liquid hydrogen/
Lide, D.R. (ed.). CRC Handbook of Chemistry and Physics. 79th ed. Boca Raton, FL: CRC Press Inc., 1998-1999., p. 4-15
Production of ammonia, ethanol, and aniline; hydrocracking, hydroforming, and hydrofining of petroleum; hydrogenation of vegetable oils; hydrogenolysis of coal; reducing agent for organic synthesis and metallic ores; reducing atmosphere to prevent oxidation; as oxyhdrogen flame for high temperatures; atomic-hydrogen welding; instrument-carrying balloons; making hydrogen chloride and hydrogen bromide; production of high-purity metals; fuel for nuclear rocket engines for hypersonic transport; missile fuel; cryogenic research.
Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 733
For more Uses (Complete) data for Hydrogen (7 total), please visit the HSDB record page.

11.1.1 Use Classification

Food additives
Hazard Classes and Categories -> Flammable - 4th degree

11.1.2 Industry Uses

  • Processing aids, not otherwise listed
  • Odor agents
  • Fuels and fuel additives
  • Intermediates
  • Fuel agents
  • Fuel
  • Not Known or Reasonably Ascertainable
  • Functional fluids (closed systems)
  • Intermediate
  • Reducing agent
  • Other (specify)

11.1.3 Consumer Uses

  • Other (specify)
  • Fuels and fuel additives
  • Not Known or Reasonably Ascertainable
  • Fuel agents
  • Processing aids, not otherwise listed
  • Flame retardants
  • Odor agents

11.2 Methods of Manufacturing

The main commercial processes for the on-purpose production of hydrogen are steam reforming, partial oxidation (coal, coke, resid), or electrolysis of water. Hydrogen is also commercially produced as a by-product of chemical processes (ethylene crackers, styrene, MTBE etc) or gasoline manufacturing (catalytic reforming).
Baade WF et al; Hydrogen. Kirk-Othmer Encyclopedia of Chemical Technology (1999-2017). John Wiley & Sons, Inc. Online Posting Date: December 20, 2001
Obtained by passing water vapors over heated iron; by electrolysis of water or by action of hydrochloric acid or sulfuric acid on iron or zinc; by hydrolysis of metal hydrides.
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 887
(1) Reaction of steam with natural gas (steam reforming) and susequent purification; (2) partial oxidation of hydrocarbons to carbon monoxide and interaction of carbon monoxide and steam; (3) gasification of coal; (4) dissociation of ammonia; (5) thermal or catalytic decomposition of hydrocarbons gases; (6) catalytic reforming of naphtha; (7) reaction of iron and steam; (8) catalytic reaction of methanol and steam; (9) electrolysis of water.
Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 733
Hydrogen can be produced using diverse, domestic resources including fossil fuels, such as natural gas and coal (preferentially with carbon capture, utilization, and storage); biomass grown from renewable, non-food crops; or using nuclear energy and renewable energy sources, such as wind, solar, geothermal, and hydroelectric power to split water. This diversity of potential supply sources is an important reason why hydrogen is such a promising energy carrier.
DOE; Fuel Cell technologies Office: Hydrogen Production (September, 2014). Available from, as of June 21, 2017: https://energy.gov/sites/prod/files/2014/09/f18/fcto_hydrogen_production_fs_0.pdf
Hydrogen is produced on a laboratory scale from the action of an aqueous acid on a metal or from the reaction of an alkali metal in water ... These reactions can be carried out at room temperature. Hydrogen gas can also be produced on a laboratory scale by the electrolysis of an aqueous solution. Production of hydrogen through electrolysis is also used industrially. ... Hydrogen atoms can be produced in significant quantities in the gas phase by the action of radiation on or by extreme heating of H2 (3000 K).
Baade WF et al; Hydrogen. Kirk-Othmer Encyclopedia of Chemical Technology (1999-2017). John Wiley & Sons, Inc. Online Posting Date: December 20, 2001

11.3 Formulations / Preparations

Grades: Technical, pure, from an electrolytic grade of 99.8% to ultra-pure, with less than 10 ppm impurities.
Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 733

11.4 Consumption Patterns

CHEMICAL INTERMEDIATE FOR AMMONIA, 56%; PETROLEUM REFINING, 25%; CHEMICAL INTERMEDIATE FOR METHANOL, 7%; OTHER, 12% (1980)
SRI
U.S. consumption of hydrogen in 1988: 49% as chemical intermediate for ammonia; 37% in petroleum refining; 8% as chemical intermediate for methanol; 6% as other uses
Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V13 (95) 884

11.5 U.S. Production

Aggregated Product Volume

2019: 5,000,000,000 - <10,000,000,000 lb

2018: 10,000,000,000 - <20,000,000,000 lb

2017: 5,000,000,000 - <10,000,000,000 lb

2016: 10,000,000,000 - <20,000,000,000 lb

(1977) 8.48X10+10 CU FT
SRI
(1979) 9.93X10+10 CU FT
SRI
Daily Capacity: 4,197,260 thousands of cu ft
SRI. 1999 Directory of Chemical Producers -United States. Menlo Park, CA. SRI Consulting 1999., p. 473
U.S. ... about 3 billion cu ft/yr
Lide, D.R. (ed.). CRC Handbook of Chemistry and Physics. 79th ed. Boca Raton, FL: CRC Press Inc., 1998-1999., p. 4-14
For more U.S. Production (Complete) data for Hydrogen (6 total), please visit the HSDB record page.

11.6 U.S. Exports

(1977) 5.91X10+8 CU FT
SRI
(1979) 1.27X10+8 CU FT
SRI

11.7 General Manufacturing Information

Industry Processing Sectors
  • All Other Chemical Product and Preparation Manufacturing
  • Primary Metal Manufacturing
  • Petrochemical Manufacturing
  • Plastics Material and Resin Manufacturing
  • Utilities
  • All other Petroleum and Coal Products Manufacturing
  • All Other Basic Inorganic Chemical Manufacturing
  • All Other Basic Organic Chemical Manufacturing
  • Petroleum Refineries
  • Industrial Gas Manufacturing
  • Wholesale and Retail Trade
EPA TSCA Commercial Activity Status
Hydrogen: ACTIVE
Production of hydrogen in usa alone now amounts to about 3 billion cu ft/yr.
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 94th Edition. CRC Press LLC, Boca Raton: FL 2013-2014, p. 4-17
Method of purification: by scrubbing with various solutions (especially the Girbitol absorption process). For very pure hydrogen, by diffusion through palladium.
Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 733
More efficient methods than electrolysis for obtaining hydrogen from water are under investigation. One of these is thermochemical decomposition. Another is photochemical decomposition by solar radiation, either directly or via a solar power generator. Photolytic decomposition of water with platinum catalyst has been achieved. Hydrogen can also be obtained by photolytic decomposition of hydrogen sulfide with cadmium sulfide catalyst.
Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 733
Most U.S. hydrogen production ... is used captively.
Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V13 (95) 878
For more General Manufacturing Information (Complete) data for Hydrogen (7 total), please visit the HSDB record page.

12 Identification

12.1 Analytic Laboratory Methods

For hydrogen sensors built with pure Pd nanowires, the instabilities causing baseline drifting and temperature-driven sensing behavior are limiting factors when working within a wide temperature range. To enhance the material stability, we have developed superlattice-structured palladium and copper nanowires (PdCu NWs) with random-gapped, screw-threaded, and spiral shapes achieved by wet-chemical approaches. The microstructure of the PdCu NWs reveals novel superlattices composed of lattice groups structured by four-atomic layers of alternating Pd and Cu. Sensors built with these modified NWs show significantly reduced baseline drifting and lower critical temperature (259.4 K and 261 K depending on the PdCu structure) for the reverse sensing behavior than those with pure Pd NWs (287 K). Moreover, the response and recovery times of the PdCu NWs sensor were of ~9 and ~7 times faster than for Pd NWs sensors, respectively.
Yang D et al; Sci Rep 4: 3773 (2014)
Electroless templating on DNA is established as a means to prepare high aspect ratio nanowires via aqueous reactions at room temperature. In this report we show how Pd nanowires with extremely small grain sizes (< 2 nm) can be prepared by reduction of PdCl4(2-) in the presence of lambda-DNA. In AFM images the wires are smooth and uniform in appearance, but the grain size estimated by the Scherrer treatment of line broadening in X-ray diffraction is less than the diameter of the wires from AFM (of order 10 nm). Electrical characterization of single nanowires by conductive AFM shows ohmic behavior, but with high contact resistances and a resistivity (-10(-2) omega cm) much higher than the bulk value for Pd metal (-10(-5) cm at 20 °C). These observations can be accounted for by a model of the nanowire growth mechanism which naturally leads to the formation of a granular metal. Using a simple combing technique with control of the surface hydrophilicity, DNA-templated Pd nanowires have also been prepared as networks on an Si/SiO2 substrate. These networks are highly convenient for the preparation of two-terminal electronic sensors for the detection of hydrogen gas. The response of these hydrogen sensors is presented and a model of the sensor response in terms of the diffusion of hydrogen into the nanowires is described. The granular structure of the nanowires makes them relatively poor conductors, but they retain a useful sensitivity to hydrogen gas.
Al-Hinai MN et al; Faraday Discuss 164: 71-91 (2013)
The determination of hydrogen content of an organic compound consists of complete combustion of a known quantity of the material to produce water and carbon dioxide, and determination of the amount of water. The amount of hydrogen present in the initial material is calculated from the amount of water produced. This technique can be performed on macro (0.1-0.2 g), micro (2-10 mg), or submicro (0.02-0.2 mg) scale. ... The oldest and probably most reliable technique for water determination is a gravimetric one where the water is absorbed onto a desiccant, such as magnesium perchlorate. In the macro technique, which is the most accurate, hydrogen content of a compound can be routinely determined to within +/- 0.02%. Instrumental methods, such as gas chromatography and mass spectrometry, can also be used to determine water of combustion.
Baade WF et al; Hydrogen. Kirk-Othmer Encyclopedia of Chemical Technology (1999-2017). John Wiley & Sons, Inc. Online Posting Date: December 20, 2001
To determine quantitatively the amount of hydrogen present in a gas mixture, gas chromatography using a thermal conductivity detector is often employed.
Baade WF et al; Hydrogen. Kirk-Othmer Encyclopedia of Chemical Technology (1999-2017). John Wiley & Sons, Inc. Online Posting Date: December 20, 2001

12.2 Clinical Laboratory Methods

A standardized simple, indirect method for assessing the relative energy of dietary fiber carbohydrates is not yet established. There is a need for a standardized in vivo assay. The objective of the present study was to evaluate the relative available energy (RAE) for 9 major dietary fiber materials (DFMs) based on fermentability from breath hydrogen excretion (BHE) in subjects. Fructooligosaccharide (FOS) was used as a reference. The study was conducted using a within-subject, repeated measures design and approved by the Ethical Committee of University of Nagasaki. After DFM ingestion, end-expiratory gas (750-mL) was collected at 1-hr intervals for 8 hr, as well as at 2-hr intervals between 8 hr and 14 hr, and 30 min after waking up and 24 hr after DFM ingestion. Breath hydrogen concentration was assessed with a gas chromatograph. The RAE of DFMs tested was evaluated based on the area under the curve (AUC) of BHE of FOS. Based on the ratio of AUC for 8 hr, the RAE of polydextrose, partially hydrolysed guar gum, resistant maltodextrin and partially hydrolysed alginate was 1 kcal/g, and that of glucomannan, heat-moisture treatment and high-amylose cornstarch and cellulose was 0 kcal/g, while the RAE of all tested DEMs including cellulose and glucomannan was 1 kcal/g in the calculation based on AUCs for 14 hr and 24 hr in subjects. We suggest that a breath hydrogen collection period of 14 hr or more could be used to measure RAE for a range of fiber preparations in vivo.
Oku T, Nakamura S; J Nutr Sci Vitaminol (Tokyo) 60 (4): 246-54 (2014)

13 Safety and Hazards

13.1 Hazards Identification

13.1.1 GHS Classification

1 of 6
View All
Note
Pictograms displayed are for 99.9% (1403 of 1405) of reports that indicate hazard statements. This chemical does not meet GHS hazard criteria for 0.1% (2 of 1405) of reports.
Pictogram(s)
Flammable
Compressed Gas
Signal
Danger
GHS Hazard Statements

H220 (99.8%): Extremely flammable gas [Danger Flammable gases]

H280 (76.7%): Contains gas under pressure; may explode if heated [Warning Gases under pressure]

H281 (13.7%): Contains refrigerated gas; may cause cryogenic burns or injury [Warning Gases under pressure]

Precautionary Statement Codes

P203, P210, P222, P280, P282, P336+P317, P377, P381, P403, and P410+P403

(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 1405 reports by companies from 20 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Reported as not meeting GHS hazard criteria per 2 of 1405 reports by companies. For more detailed information, please visit ECHA C&L website.

There are 19 notifications provided by 1403 of 1405 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.

13.1.2 Hazard Classes and Categories

Flam. Gas 1 (99.8%)

Press. Gas (Comp.) (76.7%)

Press. Gas (Ref. Liq.) (13.7%)

Flammable gas - category 1

Gases under pressure

13.1.3 NFPA Hazard Classification

NFPA 704 Diamond
0-4-0
NFPA Health Rating
0 - Materials that, under emergency conditions, would offer no hazard beyond that of ordinary combustible materials.
NFPA Fire Rating
4 - Materials that rapidly or completely vaporize at atmospheric pressure and normal ambient temperature or that are readily dispersed in air and burn readily.
NFPA Instability Rating
0 - Materials that in themselves are normally stable, even under fire conditions.

13.1.4 Health Hazards

Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]:

Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas. Some may be irritating if inhaled at high concentrations. Contact with gas, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite. Fire may produce irritating and/or toxic gases. (ERG, 2024)

If atmosphere does not contain enough oxygen, inhalation can cause dizziness, unconsciousness, or even death. Contact of liquid with eyes or skin causes freezing similar to burn. (USCG, 1999)
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
ERG 2024, Guide 115 (Hydrogen, compressed; Hydrogen, refrigerated liquid (cryogenic liquid))

· Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas.

· Some may be irritating if inhaled at high concentrations.

· Contact with gas, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite.

· Fire may produce irritating and/or toxic gases.

13.1.5 Fire Hazards

Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]:

EXTREMELY FLAMMABLE. Will be easily ignited by heat, sparks or flames. Will form explosive mixtures with air. Vapors from liquefied gas are initially heavier than air and spread along ground. CAUTION: Hydrogen (UN1049), Deuterium (UN1957), Hydrogen, refrigerated liquid (UN1966), Methane (UN1971) and Hydrogen and Methane mixture, compressed (UN2034) are lighter than air and will rise. Hydrogen and Deuterium fires are difficult to detect since they burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.) Vapors may travel to source of ignition and flash back. Cylinders exposed to fire may vent and release flammable gas through pressure relief devices. Containers may explode when heated. Ruptured cylinders may rocket. CAUTION: When LNG - Liquefied natural gas (UN1972) is released on or near water, product may vaporize explosively. (ERG, 2024)

Behavior in Fire: Burns with an almost invisible flame. (USCG, 1999)
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
ERG 2024, Guide 115 (Hydrogen, compressed; Hydrogen, refrigerated liquid (cryogenic liquid))

· EXTREMELY FLAMMABLE.

· Will be easily ignited by heat, sparks or flames.

· Will form explosive mixtures with air.

· Vapors from liquefied gas are initially heavier than air and spread along ground.

CAUTION: Hydrogen (UN1049), Deuterium (UN1957), Hydrogen, refrigerated liquid (UN1966), Methane (UN1971) and Hydrogen and Methane mixture, compressed (UN2034) are lighter than air and will rise. Hydrogen and Deuterium fires are difficult to detect since they burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.)

· Vapors may travel to source of ignition and flash back.

· Cylinders exposed to fire may vent and release flammable gas through pressure relief devices.

· Containers may explode when heated.

· Ruptured cylinders may rocket.

CAUTION: When LNG - Liquefied natural gas (UN1972) is released on or near water, product may vaporize explosively.

Extremely flammable. Many reactions may cause fire or explosion. Gas/air mixtures are explosive.

13.1.6 Hazards Summary

Simple asphyxiant; Contact with evaporating liquid can cause frostbite; [HSDB]

13.1.7 Fire Potential

Highly dangerous fire and severe explosion hazard when exposed to heat, flame, or oxidizers.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 1985
... Sudden release of hydrogen into the atmosphere from storage above 79 bars may cause spontaneous ignition. ...
Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990, p. 1186

13.2 Safety and Hazard Properties

13.2.1 Flammable Limits

Lower: 4.0%; upper: 75% (% by vol)
National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-72

13.2.2 Lower Explosive Limit (LEL)

4 % (USCG, 1999)
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.

13.2.3 Upper Explosive Limit (UEL)

75 % (USCG, 1999)
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.

13.2.4 Critical Temperature & Pressure

Critical temperature: -239.9 °C; critical pressure: 12.8 atm
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 887

13.2.5 Physical Dangers

The gas mixes well with air, explosive mixtures are easily formed. The gas is lighter than air.

13.2.6 Explosive Limits and Potential

Flammable or explosive when mixed with air, O2, chlorine.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 1985
Lower: 4.1%; upper: 74.2%
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 1985
Explosive limits , vol% in air: 4-75

13.3 First Aid Measures

Inhalation First Aid
Fresh air, rest.
Skin First Aid
ON FROSTBITE: rinse with plenty of water, do NOT remove clothes. Refer immediately for medical attention.
Eye First Aid
ON FROSTBITE: rinse with plenty of water. Refer immediately for medical attention.

13.3.1 First Aid

Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]:

Refer to the "General First Aid" section. Specific First Aid: Clothing frozen to the skin should be thawed before being removed. In case of contact with liquefied gas, only medical personnel should attempt thawing frosted parts. In case of burns, immediately cool affected skin for as long as possible with cold water. Do not remove clothing if adhering to skin. (ERG, 2024)

The only effect of exposure to liquid hydrogen is that caused by its unusually low temperature and its action as a simple asphyxiant.

INHALATION: if victim is unconscious (due to oxygen deficiency), move him to fresh air and apply resuscitation methods; call physician.

EYES: treat for frostbite.

SKIN: treat for frostbite; soak in lukewarm water; get medical attention if burn is severe. (USCG, 1999)

U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
ERG 2024, Guide 115 (Hydrogen, compressed; Hydrogen, refrigerated liquid (cryogenic liquid))

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.

Specific First Aid:

· Clothing frozen to the skin should be thawed before being removed.

· In case of contact with liquefied gas, only medical personnel should attempt thawing frosted parts.

· In case of burns, immediately cool affected skin for as long as possible with cold water. Do not remove clothing if adhering to skin.

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

13.4 Fire Fighting

Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]:

DO NOT EXTINGUISH A LEAKING GAS FIRE UNLESS LEAK CAN BE STOPPED. CAUTION: Hydrogen (UN1049), Deuterium (UN1957), Hydrogen, refrigerated liquid (UN1966) and Hydrogen and Methane mixture, compressed (UN2034) will burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.).

SMALL FIRE: Dry chemical or CO2.

LARGE FIRE: Water spray or fog. If it can be done safely, move undamaged containers away from the area around the fire. CAUTION: For LNG - Liquefied natural gas (UN1972) pool fires, DO NOT USE water. Use dry chemical or high-expansion foam.

FIRE INVOLVING TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Do not direct water at source of leak or safety devices; icing may occur. 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. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2024)

Shut off supply; if not possible and no risk to surroundings, let the fire burn itself out. In other cases extinguish with water spray, powder, carbon dioxide. In case of fire: keep cylinder cool by spraying with water. Combat fire from a sheltered position.

13.4.1 Fire Fighting Procedures

To fight fire, stop flow of gas.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 1985
Approach fire with caution as high-temperature flame is practically invisible. Stop flow of gas before extinguishing fire. Use water spray to keep fire-exposed containers cool. Use flooding quantities of water as fog or spray. /Hydrogen, refrigerated liquid/
National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 49-86
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide. Wear self-contained breathing apparatus for firefighting if necessary. Use water spray to cool unopened containers.
Sigma-Aldrich; Safety Data Sheet for Hydrogen. Product Number: , Version 3.10 (Revision Date 05/27/2016). Available from, as of June 16, 2017: https://www.sigmaaldrich.com/safety-center.html

13.5 Accidental Release Measures

Public Safety: ERG 2024, Guide 115 (Hydrogen, compressed; Hydrogen, refrigerated liquid (cryogenic liquid))

· 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.

· Keep unauthorized personnel away.

· Stay upwind, uphill and/or upstream.

· Many gases are heavier than air and will spread along the ground and collect in low or confined areas (sewers, basements, tanks, etc.).

Spill or Leak: ERG 2024, Guide 115 (Hydrogen, compressed; Hydrogen, refrigerated liquid (cryogenic liquid))

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

· All equipment used when handling the product must be grounded.

· Do not touch or walk through spilled material.

· Stop leak if you can do it without risk.

· If possible, turn leaking containers so that gas escapes rather than liquid.

· Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material.

· Do not direct water at spill or source of leak.

CAUTION: For LNG - Liquefied natural gas (UN1972), DO NOT apply water, regular or alcohol-resistant foam directly on spill. Use a high-expansion foam if available to reduce vapors.

· Prevent spreading of vapors through sewers, ventilation systems and confined areas.

· Isolate area until gas has dispersed.

CAUTION: When in contact with refrigerated/cryogenic liquids, many materials become brittle and are likely to break without warning.

13.5.1 Isolation and Evacuation

Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 100 meters (330 feet) in all directions.

LARGE SPILL: Consider initial downwind evacuation for at least 800 meters (1/2 mile).

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 1600 meters (1 mile) in all directions; also, consider initial evacuation for 1600 meters (1 mile) in all directions. In fires involving Liquefied Petroleum Gases (LPG) (UN1075), Butane (UN1011), Butylene (UN1012), Isobutylene (UN1055), Propylene (UN1077), Isobutane (UN1969), and Propane (UN1978), also refer to the "BLEVE - Safety Precautions" section. (ERG, 2024)

Evacuation: ERG 2024, Guide 115 (Hydrogen, compressed; Hydrogen, refrigerated liquid (cryogenic liquid))

Immediate precautionary measure

· Isolate spill or leak area for at least 100 meters (330 feet) in all directions.

Large Spill

· Consider initial downwind evacuation for at least 800 meters (1/2 mile).

Fire

· If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 1600 meters (1 mile) in all directions; also, consider initial evacuation for 1600 meters (1 mile) in all directions.

· In fires involving Liquefied Petroleum Gases (LPG) (UN1075), Butane (UN1011), Butylene (UN1012), Isobutylene (UN1055), Propylene (UN1077), Isobutane (UN1969), and Propane (UN1978), also refer to the "BLEVE - Safety Precautions" section.

13.5.2 Spillage Disposal

Evacuate danger area! Consult an expert! Ventilation. Remove all ignition sources. Remove vapour with fine water spray.

13.5.3 Cleanup Methods

ACCIDENTAL RELEASE MEASURES: Personal precautions, protective equipment and emergency procedures: Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Remove all sources of ignition. Evacuate personnel to safe areas. Beware of vapors accumulating to form explosive concentrations. Vapors can accumulate in low areas. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Methods and materials for containment and cleaning up: Clean up promptly by sweeping or vacuum.
Sigma-Aldrich; Safety Data Sheet for Hydrogen. Product Number: , Version 3.10 (Revision Date 05/27/2016). Available from, as of June 16, 2017: https://www.sigmaaldrich.com/safety-center.html
Eliminate all ignition sources. Approach release from upwind. Stop or control the leak, if this can be done without undue risk. Use water spray to disperse vapors and protect personnel. /Hydrogen, refrigerated liquid/
National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 49-86

13.5.4 Disposal Methods

SRP: 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 air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.
Product: Contact a licensed professional waste disposal service to dispose of this material. Burn in a chemical incinerator equipped with an afterburner and scrubber but exert extra care in igniting as this material is highly flammable. Offer surplus and non-recyclable solutions to a licensed disposal company. Contaminated packaging: Dispose of as unused product
Sigma-Aldrich; Safety Data Sheet for Hydrogen. Product Number: , Version 3.10 (Revision Date 05/27/2016). Available from, as of June 16, 2017: https://www.sigmaaldrich.com/safety-center.html

13.5.5 Preventive Measures

Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday.
Sigma-Aldrich; Safety Data Sheet for Hydrogen. Product Number: , Version 3.10 (Revision Date 05/27/2016). Available from, as of June 16, 2017: https://www.sigmaaldrich.com/safety-center.html
Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands.
Sigma-Aldrich; Safety Data Sheet for Hydrogen. Product Number: , Version 3.10 (Revision Date 05/27/2016). Available from, as of June 16, 2017: https://www.sigmaaldrich.com/safety-center.html
Avoid inhalation of vapor or mist. Use explosion-proof equipment. Keep away from sources of ignition - No smoking. Take measures to prevent the build up of electrostatic charge.
Sigma-Aldrich; Safety Data Sheet for Hydrogen. Product Number: , Version 3.10 (Revision Date 05/27/2016). Available from, as of June 16, 2017: https://www.sigmaaldrich.com/safety-center.html

13.6 Handling and Storage

13.6.1 Nonfire Spill Response

Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Do not touch or walk through spilled material. Stop leak if you can do it without risk. If possible, turn leaking containers so that gas escapes rather than liquid. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Do not direct water at spill or source of leak. CAUTION: For LNG - Liquefied natural gas (UN1972), DO NOT apply water, regular or alcohol-resistant foam directly on spill. Use a high-expansion foam if available to reduce vapors. Prevent spreading of vapors through sewers, ventilation systems and confined areas. Isolate area until gas has dispersed. CAUTION: When in contact with refrigerated/cryogenic liquids, many materials become brittle and are likely to break without warning. (ERG, 2024)

13.6.2 Safe Storage

Fireproof. Cool. Ventilation along the floor and ceiling. Separated from oxidizing materials.

13.6.3 Storage Conditions

Store in a cool, dry, well-ventilated location. Outside or detached storage is preferred. Isolate from oxygen, halogens, other oxidizing materials. /Hydrogen, refrigerated liquid/
National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 49-86
A safe storage method for hydrogen for possible use as automotive fuel involves the use of metal hydrides from which the hydrogen is released at specified temperatures. Iron titanium hydride has been found the most satisfactory.
Larranaga, M.D., Lewis, R.J. Sr., Lewis, R.A.; Hawley's Condensed Chemical Dictionary 16th Edition. John Wiley & Sons, Inc. Hoboken, NJ 2016., p. 733
Keep container tightly closed in a dry and well-ventilated place. Contents under pressure. Storage class (TRGS 510): Gases
Sigma-Aldrich; Safety Data Sheet for Hydrogen. Product Number: , Version 3.10 (Revision Date 05/27/2016). Available from, as of June 16, 2017: https://www.sigmaaldrich.com/safety-center.html

13.7 Exposure Control and Personal Protection

Protective Clothing: ERG 2024, Guide 115 (Hydrogen, compressed; Hydrogen, refrigerated liquid (cryogenic liquid))

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

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

· Always wear thermal protective clothing when handling refrigerated/cryogenic liquids.

13.7.1 Threshold Limit Values (TLV)

Simple asphyxiant; Explosion hazard: the substance is a flammable asphyxiant or excursions above the TLV could approach 10% of the lower explosive limit. /A simple asphyxiant may not be assigned a TLV because the limiting factor is the available oxygen./
American Conference of Governmental Industrial Hygienists TLVs and BEIs. Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. Cincinnati, OH 2017, p. 35

13.7.2 Emergency Response Planning Guidelines

Emergency Response: ERG 2024, Guide 115 (Hydrogen, compressed; Hydrogen, refrigerated liquid (cryogenic liquid))

· DO NOT EXTINGUISH A LEAKING GAS FIRE UNLESS LEAK CAN BE STOPPED.

CAUTION: Hydrogen (UN1049), Deuterium (UN1957), Hydrogen, refrigerated liquid (UN1966) and Hydrogen and Methane mixture, compressed (UN2034) will burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.)

Small Fire

· Dry chemical or CO2.

Large Fire

· Water spray or fog.

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

CAUTION: For LNG - Liquefied natural gas (UN1972) pool fires, DO NOT USE water. Use dry chemical or high-expansion foam.

Fire Involving Tanks

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

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

· Do not direct water at source of leak or safety devices; icing may occur.

· 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.

· For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn.

13.7.3 Inhalation Risk

On loss of containment this substance can cause suffocation by lowering the oxygen content of the air in confined areas.

13.7.4 Effects of Short Term Exposure

Asphyxiation. Exposure to cold gas could cause frostbite.

13.7.5 Personal Protective Equipment (PPE)

Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]:

Wear positive pressure self-contained breathing apparatus (SCBA). Structural firefighters' protective clothing provides thermal protection but only limited chemical protection. Always wear thermal protective clothing when handling refrigerated/cryogenic liquids. (ERG, 2024)

Safety goggles or face shield; insulated gloves and long sleeves; cuffless trousers worn outside boots or over high-top shoes to shed spilled liquid; self-contained breathing apparatus containing air (never use oxygen). (USCG, 1999)
U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
Eye/face protection: Face shield and safety glasses. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
Sigma-Aldrich; Safety Data Sheet for Hydrogen. Product Number: , Version 3.10 (Revision Date 05/27/2016). Available from, as of June 16, 2017: https://www.sigmaaldrich.com/safety-center.html
Wear special protective clothing and positive pressure self-contained breathing apparatus. /Hydrogen, refrigerated liquid/
National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 49-86
Skin protection: Handle with gloves.
Sigma-Aldrich; Safety Data Sheet for Hydrogen. Product Number: , Version 3.10 (Revision Date 05/27/2016). Available from, as of June 16, 2017: https://www.sigmaaldrich.com/safety-center.html
Body Protection: Impervious clothing. Flame retardant antistatic protective clothing. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Sigma-Aldrich; Safety Data Sheet for Hydrogen. Product Number: , Version 3.10 (Revision Date 05/27/2016). Available from, as of June 16, 2017: https://www.sigmaaldrich.com/safety-center.html
Respiratory protection: Where risk assessment shows air-purifying respirators are appropriate use a full-face respirator with multipurpose combination (US) or type AXBEK (EN 14387) respirator cartridges as a backup to engineering controls. If the respirator is the sole means of protection, use a full-face supplied air respirator. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Sigma-Aldrich; Safety Data Sheet for Hydrogen. Product Number: , Version 3.10 (Revision Date 05/27/2016). Available from, as of June 16, 2017: https://www.sigmaaldrich.com/safety-center.html

13.7.6 Preventions

Fire Prevention
NO open flames, NO sparks and NO smoking. Closed system, ventilation, explosion-proof electrical equipment and lighting. Use non-sparking handtools. Do not handle cylinders with oily hands.
Exposure Prevention
Use appropriate engineering controls.
Inhalation Prevention
Use ventilation.
Skin Prevention
Cold-insulating gloves.
Eye Prevention
Wear face shield.

13.8 Stability and Reactivity

13.8.1 Air and Water Reactions

Highly flammable.

13.8.2 Reactive Group

Reducing Agents, Weak

13.8.3 Reactivity Alerts

Highly Flammable
13.8.3.1 CSL Reaction Information
CSL No
Warning Message
"A safety letter from Merck & Co. chemists titled “Nitric Oxide at High Pressure” (C&EN, Jan. 30, page 6) described two explosions during depressurization of a reaction between NO and methanol under basic conditions. The products in a model system with sodium methoxide were described as nitrous oxide and formic acid, presumably as sodium formate. A potential danger in this system should be pointed out: Sodium formate undergoes thermal decomposition to give hydrogen gas (J. Am. Chem. Soc.,DOI: 10.1021/ja02245a004), which explodes spontaneously in the presence of nitrous oxide above critical limits (J. Am. Chem. Soc., DOI: 10.1021/ja01179a036), even in the absence of a catalyst or source of ignition. The presence of hydrogen and nitrous oxide above a reaction mixture was undoubtedly the cause of an explosion and fire in my laboratory in 1981 during workup of a reaction between sodium and nitric oxide. The major product of the reaction is cis-sodium hyponitrite, which decomposes immediately in water to form sodium hydroxide and nitrous oxide. The employee, a biology major who was badly burned, had carried out the reaction a number of times without incident. This time he tried twice and failed to disperse about 30 g of sodium in toluene and, without consulting me, decided to continue the reaction. The explosion occurred as he was attempting to destroy the unreacted sodium, a lump too large to remove from the flask, by dropwise addition of water. Most of the sodium had reacted at the time of the explosion, and there was no indication of mechanical failure. At the time, I was unaware of the extreme incompatibility of the two gases, and the accident was extremely puzzling. The reaction mixture was close to room temperature and was stirred rapidly while the headspace was flushed with a stream of nitrogen. When I arrived at the laboratory a few minutes after the accident, nitrogen was still flowing from the burned-off end of the plastic tubing. Since that time, I noticed a reference to the “hydrogen explosion” in the ancient chemical literature as a way to identify nitrous oxide." (reprint of the full-text)
GHS Category
Explosive
Reaction Scale
Medium (up to 100g)
Reference Source
Literature Reference
Modified Date
10/15/2022
Create Date
10/14/2022

13.8.4 Reactivity Profile

Finely divided platinum and some other metals will cause a mixture of hydrogen and oxygen to explode at ordinary temperatures. If a jet of hydrogen in air impinges on platinum black the metal surface gets hot enough to ignite the gases, [Mellor 1:325(1946-1947)]. Explosive reactions occur upon ignition of mixtures of nitrogen trifluoride with good reducing agents such as ammonia, hydrogen, hydrogen sulfide or methane. Mixtures of hydrogen, carbon monoxide, or methane and oxygen difluoride are exploded when a spark is discharged, [Mellor 2, Supp. 1:192(1956)]. An explosion occurred upon heating 1'-pentol and 1''-pentol under hydrogen pressure. It appears that this acetylenic compound under certain conditions suddenly breaks down to form elemental carbon, hydrogen, and carbon monoxide with the release of sufficient energy to develop pressures in excess of 1000 atmospheres, [AIChE Loss Prevention, p1, (1967)].
Finely divided platinum and some other metals will cause a mixture of hydrogen and oxygen to explode at ordinary temperatures. If a jet of hydrogen in air impinges on platinum black the metal surface gets hot enough to ignite the gases, [Mellor 1:325(1946-1947)]. Explosive reactions occur upon ignition of mixtures of nitrogen trifluoride with good reducing agents such as ammonia, hydrogen, hydrogen sulfide or methane. Mixtures of hydrogen, carbon monoxide, or methane and oxygen difluoride are exploded when a spark is discharged, [Mellor 2, Supp. 1:192(1956)]. An explosion occurred upon heating 1'-pentol and 1''-pentol under hydrogen pressure. It appears that this acetylenic compound under certain conditions suddenly breaks down to form elemental carbon, hydrogen, and carbon monoxide with the release of sufficient energy to develop pressures in excess of 1000 atmospheres, [AIChE Loss Prevention, p1, (1967)]. Contact of very cold liquefied gas with water may result in vigorous or violent boiling of the product and extremely rapid vaporization due to the large temperature differences involved. If the water is hot, there is the possibility that a liquid "superheat" explosion may occur. Pressures may build to dangerous levels if liquid gas contacts water in a closed container, [Handling Chemicals Safely 1980].

13.8.5 Hazardous Reactivities and Incompatibilities

Release of hydrogen @ 47.5 bar into a vented 17.5-l chromium-plated sphere caused explosive ignition. /Hydrogen/
Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990, p. 1186-7
Hydrogen ignites in bromine fluoride at ambient temp.
Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990, p. 90
Mixtures of iodine heptafluoride with hydrogen explode on heating or sparking.
Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990, p. 1127
... Calcium, barium, and strontium react readily, sometimes igniting, in hydrogen above 300 °C. ...
Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990, p. 1189
For more Hazardous Reactivities and Incompatibilities (Complete) data for Hydrogen (19 total), please visit the HSDB record page.

13.9 Transport Information

13.9.1 DOT Emergency Guidelines

/GUIDE 115 GASES - FLAMMABLE (Including Refrigerated Liquids)/ Fire or Explosion: EXTREMELY FLAMMABLE. Will be easily ignited by heat, sparks or flames. Will form explosive mixtures with air. Vapors from liquefied gas are initially heavier than air and spread along ground. CAUTION: Hydrogen (UN1049), Deuterium (UN1957), Hydrogen, refrigerated liquid (UN1966) and Methane (UN1971) are lighter than air and will rise. Hydrogen and Deuterium fires are difficult to detect since they burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.) Vapors may travel to source of ignition and flash back. Cylinders exposed to fire may vent and release flammable gas through pressure relief devices. Containers may explode when heated. Ruptured cylinders may rocket. /Hydrogen; Hydrogen, compressed; Hydrogen, refrigerated liquid (cryogenic liquid)/
U.S. Department of Transportation. 2016 Emergency Response Guidebook. Washington, D.C. 2016
/GUIDE 115 GASES - FLAMMABLE (Including Refrigerated Liquids)/ Health: Vapors may cause dizziness or asphyxiation without warning. Some may be irritating if inhaled at high concentrations. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire may produce irritating and/or toxic gases. /Hydrogen; Hydrogen, compressed; Hydrogen, refrigerated liquid (cryogenic liquid)/
U.S. Department of Transportation. 2016 Emergency Response Guidebook. Washington, D.C. 2016
/GUIDE 115 GASES - FLAMMABLE (Including Refrigerated Liquids)/ Public Safety: CALL Emergency Response Telephone Number on Shipping Paper first. If Shipping Paper not available or no answer, refer to appropriate telephone number listed on the inside back cover. As an immediate precautionary measure, isolate spill or leak area for at least 100 meters (330 feet) in all directions. Keep unauthorized personnel away. Stay upwind, uphill and/or upstream. Many gases are heavier than air and will spread along ground and collect in low or confined areas (sewers, basements, tanks). /Hydrogen; Hydrogen, compressed; Hydrogen, refrigerated liquid (cryogenic liquid)/
U.S. Department of Transportation. 2016 Emergency Response Guidebook. Washington, D.C. 2016
/GUIDE 115 GASES - FLAMMABLE (Including Refrigerated Liquids)/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Structural firefighters' protective clothing will only provide limited protection. Always wear thermal protective clothing when handling refrigerated/cryogenic liquids. /Hydrogen; Hydrogen, compressed; Hydrogen, refrigerated liquid (cryogenic liquid)/
U.S. Department of Transportation. 2016 Emergency Response Guidebook. Washington, D.C. 2016
For more DOT Emergency Guidelines (Complete) data for Hydrogen (8 total), please visit the HSDB record page.

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

UN 1966; Hydrogen, refrigerated liquid (cryogenic liquid)
UN 1049; Hydrogen, compressed
IMO 2.1; Hydrogen, compressed; Hydrogen, refrigerated liquid

13.9.3 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 (USDOT); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of June 27, 2017: 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. Hydrogen, compressed; and hydrogen, refrigerated liquid are included on the dangerous goods list. /Hydrogen, compressed; hydrogen, refrigerated liquid/
International Air Transport Association. Dangerous Goods Regulations. 57th Edition. Montreal, Quebec Canada. 2016., p. 263, 264
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. Hydrogen, compressed; and hydrogen, refrigerated liquid are included on the dangerous goods list. /Hydrogen, compressed; hydrogen, refrigerated liquid/
International Maritime Organization. IMDG Code. International Maritime Dangerous Goods Code Volume 2 2014, p. 44, 95

13.9.4 DOT Label

Flammable Gas

13.9.5 EC Classification

Symbol: F+; R: 12; S: (2)-9-16-33

13.9.6 UN Classification

UN Hazard Class: 2.1

13.10 Regulatory Information

The Australian Inventory of Industrial Chemicals
Chemical: Hydrogen
New Zealand EPA Inventory of Chemical Status
Hydrogen: HSNO Approval: HSR001002 Approved with controls

13.10.1 DHS Chemicals of Interest (COI)

Chemicals of Interest(COI)
Hydrogen
Release: Minimum Concentration (%)
1
Release: Screening Threshold Quantities (in pounds)
10000
Security Issue: Release - Flammables
Flammable chemical that can be released at a facility.

13.11 Other Safety Information

Chemical Assessment
IMAP assessments - Hydrogen: Human health tier I assessment

13.11.1 Other Hazardous Reactions

Conditions to avoid: Heat, flames and sparks.
Sigma-Aldrich; Safety Data Sheet for Hydrogen. Product Number: , Version 3.10 (Revision Date 05/27/2016). Available from, as of June 16, 2017: https://www.sigmaaldrich.com/safety-center.html
Palladium oxide glows in contact with hydrogen at ambient temperature.
Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990, p. 1393
Contact with hydrogen causes unheated palladium trifluoride to be reduced incandescently.
Bretherick, L. Handbook of Reactive Chemical Hazards. 4th ed. Boston, MA: Butterworth-Heinemann Ltd., 1990, p. 1116

13.11.2 Special Reports

Harper SR, Pohland FG; Recent developments in hydrogen management during anaerobic biological wastewater treatment; Biotechnol Bioeng 28 (4): 585-602 (1986).

14 Toxicity

14.1 Toxicological Information

14.1.1 Toxicity Summary

IDENTIFICATION AND USE: Hydrogen is a colorless gas. Its many uses include the following: production of ammonia, ethanol, and aniline; hydrocracking, hydroforming, and hydrofining of petroleum; hydrogenation of vegetable oils; hydrogenolysis of coal; reducing agent for organic synthesis and metallic ores; reducing atmosphere to prevent oxidation; as oxyhydrogen flame for high temperatures; atomic-hydrogen welding; instrument-carrying balloons; making hydrogen chloride and hydrogen bromide; production of high-purity metals; fuel for nuclear rocket engines for hypersonic transport; missile fuel; cryogenic research. In addition, hydrogen is a versatile energy carrier that can be used to power nearly every end-use energy need (Fuel cells). Molecular hydrogen (H2) emerged as a novel therapeutic agent, with antioxidant, anti-inflammatory and anti-apoptotic effects demonstrated in plethora of animal disease models and human studies. HUMAN STUDIES: Hydrogen is a simple asphyxiant. Contact with liquid hydrogen will cause frostbite or severe burns of the skin. Hydrogen-rich water has been tested for treating oxidative stress-induced disorders because of its reactive oxygen species scavenging abilities. Hydrogen therapy may be an effective and specific innovative treatment for exercise-induced oxidative stress and sports injury, with potential for the improvement of exercise performance. ANIMAL STUDIES: A large bubble of the gas injected into anterior chamber of rabbit eyes was absorbed within three days and caused no injury. H2 was believed to be inert and nonfunctional in mammalian cells. More recently it was demonstrated that H2 reacts with highly reactive oxidants such as hydroxyl radical and peroxynitrite inside cells. Beneficial effects of molecular hydrogen in animal models were observed especially in oxidative stress-mediated diseases, such as diabetes mellitus, brain stem infarction, rheumatoid arthritis, or neurodegenerative diseases. H2 affects cell signal transduction.

14.1.2 Exposure Routes

Exposure mainly occurs via inhalation.

14.1.3 Symptoms

Inhalation Exposure
Dizziness. Headache. Lethargy. Suffocation.
Skin Exposure
ON CONTACT WITH GAS: FROSTBITE.

14.1.4 Adverse Effects

Other Poison - Simple Asphyxiant

14.1.5 Interactions

Substantial evidence indicates that molecular hydrogen (H2) has beneficial vascular effects because of its antioxidant and/or anti-inflammatory effects. Thus, hydrogen-rich water may prove to be an effective anti-aging drink. This study examined the effects of H2 on endothelial senescence and clarified the mechanisms involved. Hydrogen-rich medium was produced by a high-purity hydrogen gas generator. Human umbilical vein endothelial cells (HUVECs) were incubated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for various time periods in normal or hydrogen-rich medium. The baseline H2concentration in hydrogen-rich medium was 0.55 +/- 0.07 mmol/L. This concentration gradually decreased, and H2 was almost undetectable in medium after 12 hr. At 24 hr after TCDD exposure, HUVECs treated with TCDD exhibited increased 8OHdG and acetyl-p53 expression, decreased nicotinamide adenine dinucleotide (NAD(+))/NADH ratio, impaired Sirt1 activity, and enhanced senescence-associated beta-galactosidase. However, HUVECs incubated in hydrogen-rich medium did not exhibit these TCDD-induced changes accompanying Nrf2 activation, which was observed even after H2 was undetectable in the medium. Chrysin, an inhibitor of Nrf2, abolished the protective effects of H2 on HUVECs. H2 has long-lasting antioxidant and anti-aging effects on vascular endothelial cells through the Nrf2 pathway, even after transient exposure to H2. Hydrogen-rich water may thus be a functional drink that increases longevity. /Hydrogen-rich water/
Hara F et al; Circ J 80 (9): 2037-46 (2016)
We observed the effect of hydrogen-rich medium on lipopolysaccharide (LPS)-induced human umbilical vein endothelial cells (HUVECs), hyaline leukocyte conglutination, and permeability of the endothelium. Endotheliocytes were inoculated on 6-well plates and randomly divided into 4 groups: control, H2, LPS, LPS+H2, H2, and LPS+H2 in saturated hydrogen-rich medium. We applied Wright's staining to observe conglutination of hyaline leukocytes and HUVECs, flow cytometry to determine the content of vascular cell adhesion protein 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1), enzyme-linked immunosorbent assay to measure the E-selectin concentration in the cell liquor, the transendothelial electrical resistance (TEER) to test the permeability of endothelial cells, and Western blot and immunofluorescence to test the expression and distribution of vascular endothelial (VE)-cadherin. Compared with control cells, there was an increase in endothelium-hyaline leukocyte conglutination, a reduction in VCAM-1, ICAM-1, and E-selectin, and the TEER value increased obviously. Compared with LPS, there was an obvious reduction in the conglutination of LPS+H2 cells, a reduction in VCAM-1, ICAM-1, and E-selectin levels, and a reduction in the TEER-resistance value, while the expression of VE-cadherin increased. Fluorescence results showed that, compared with control cells, the VE-cadherin in LPS cells was in-complete at the cell joints. Compared with LPS cells, the VE-cadherin in LPS+H2 cells was even and complete at the cell joints. Liquid rich in hydrogen could reduce LPS-induced production of adhesion molecules and endothelium-hyaline leukocyte conglutination, and influence the expression and distribution of VE-cadherin to regulate the permeability of the endothelium. /Hydrogen-rich medium/
Yu Y et al; Genet Mol Res 14 (2): 6202-12 (2015)
Maternal inflammation is associated with spontaneous preterm birth and respiratory impairment among premature infants. Recently, molecular hydrogen (H2) has been reported to have a suppressive effect on oxidative stress and inflammation. The aim of this study was to evaluate the effects of H2 on fetal lung injury caused by maternal inflammation. Cell viability and the production of interleukin-6 (IL-6) and reactive oxygen species (ROS) were examined by treatment with lipopolysaccharide (LPS) contained in ordinal or H2-rich medium (HM) using a human lung epithelial cell line, A549. Pregnant Sprague Dawley rats were divided into three groups: Control, LPS, and HW + LPS groups. Rats were injected with phosphate-buffered saline (Control) or LPS intraperitoneally (LPS) on gestational day 19 and provided H2 water (HW) ad libitum for 24 hr before LPS injection (HW + LPS). Fetal lung samples were collected on day 20, and the levels of apoptosis, oxidative damage, IL-6, and vascular endothelial growth factor (VEGF) were evaluated using immunohistochemistry. The number of apoptotic cells, and levels of ROS and IL-6 were significantly increased by LPS treatment, and repressed following cultured with HM in A549 cells. In the rat models, the population positive for cleaved caspase-3, 8-hydroxy-2'-deoxyguanosine, IL-6, and VEGF was significantly increased in the LPS group compared with that observed in the Control group and significantly decreased in the HW + LPS group. In this study, LPS administration induced apoptosis and oxidative damage in fetal lung cells that was ameliorated by maternal H2 intake. Antenatal H2 administration may decrease the pulmonary mobility associated with inflammation in premature infants. /Hydrogen-rich medium/
Hattori Y et al; Free Radic Res 49 (8): 1026-37 (2015)
An anesthetized rat preparation was used for breathing studies in hyperbaric H2/CO2 atmospheres in which total gaseous pressure was varied in the safe pressure range 8.3-19.1 atm. PCO2 (partial pressure of CO2) was studied at levels of 0.05 and 0.10 atm. The response variables measured were respiration rate, blood pH and an isotonic index of diaphragm twitch amplitude, in the presence of He/O2 gas mixtures used for compression and H2/O2/Co2 saturation gases. The rat preparation can be well maintained in H2/O2 environments at pressures in excess of 8 atm. Elevated PCO2 in these environments can evoke rapid increases in respiration rate and twitch amplitude, without any marked changes in blood pH. Graded increases in PH2 (partial pressure of H2) are able to lower and ultimately abolish the effects of either 0.05 or 0.10 atm levels of CO2 in breathing parameters. The intrinsic ability of hyperbaric H2 to effect a CO2-sparing action on this preparation is greater than that previously seen with hyperbaric Ar or He. The potency sequence for the sparing action by the inert component of the hyperbaric breathing gas is H2 > Ar > He.
Friess SL et al; Toxicol Appl Pharmacol; 46 (3): 717-726 (1978; RECD. 1979)
For more Interactions (Complete) data for Hydrogen (30 total), please visit the HSDB record page.

14.1.6 Antidote and Emergency Treatment

Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Flammable gases/
Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3rd revised edition, Elsevier Mosby, St. Louis, MO 2007, p. 140-1
Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations as necessary. 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 0.9% saline (NS) during transport ... . Treat frostbite with rapid rewarming ... . /Flammable gases/
Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3rd revised edition, Elsevier Mosby, St. Louis, MO 2007, p. 141
Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Flammable gases/
Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3rd revised edition, Elsevier Mosby, St. Louis, MO 2007, p. 141
Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Simple asphyxiants and related compounds/
Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3rd revised edition, Elsevier Mosby, St. Louis, MO 2007, p. 449
For more Antidote and Emergency Treatment (Complete) data for Hydrogen (6 total), please visit the HSDB record page.

14.1.7 Human Toxicity Excerpts

/SIGNS AND SYMPTOMS/ No specific toxic action. In high concn can act as a simple asphyxiant.
The Merck Index. 10th ed. Rahway, New Jersey: Merck Co., Inc., 1983., p. 695
/SIGNS AND SYMPTOMS/ Contact with cryogenic liquid hydrogen will cause frostbite or severe burns of the skin. Simple asphyxiant.
National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 49-86
/SIGNS AND SYMPTOMS/ The relation between the /CNS depressant/ effect of nitrogen and that of hydrogen is 1:0.26.
International Labour Office. Encyclopedia of Occupational Health and Safety. Vols. I&II. Geneva, Switzerland: International Labour Office, 1983., p. 1087
/SIGNS AND SYMPTOMS/ Hydrogen has no known toxic effect on the eye.
Grant, W. M. Toxicology of the Eye. 2nd ed. Springfield, Illinois: Charles C. Thomas, 1974., p. 559
For more Human Toxicity Excerpts (Complete) data for Hydrogen (11 total), please visit the HSDB record page.

14.1.8 Non-Human Toxicity Excerpts

/LABORATORY ANIMALS: Acute Exposure/ The nuclear protein high-mobility group box 1 (HMGB1) is a key trigger for the inflammatory reaction during liver ischemia reperfusion injury (IRI). Hydrogen treatment was recently associated with down-regulation of the expression of HMGB1 and pro-inflammatory cytokines during sepsis and myocardial IRI, but it is not known whether hydrogen has an effect on HMGB1 in liver IRI. A rat model of 60 minutes 70% partial liver ischemia reperfusion injury was used. Hydrogen enriched saline (2.5, 5 or 10 mL/kg) was injected intraperitoneally 10 minutes before hepatic reperfusion. Liver injury was assessed by serum alanine aminotransferase (ALT) enzyme levels and histological changes. We also measured malondialdehyde (MDA), hydroxynonenal (HNE) and 8-hydroxy-guanosine (8-OH-G) levels as markers of the peroxidation injury induced by reactive oxygen species (ROS). In addition, pro-inflammatory cytokines including TNF-a and IL-6, and high mobility group box B1 protein (HMGB1) were measured as markers of post ischemia-reperfusion inflammation. Hydrogen enriched saline treatment significantly attenuated the severity of liver injury induced by ischemia-reperfusion. The treatment group showed reduced serum ALT activity and markers of lipid peroxidation and post ischemia reperfusion histological changes were reduced. Hydrogen enriched saline treatment inhibited HMGB1 expression and release, reflecting a reduced local and systemic inflammatory response to hepatic ischemia reperfusion. These results suggest that, in our model, hydrogen enriched saline treatment is protective against liver ischemia-reperfusion injury. This effect may be mediated by both the anti-oxidative and anti-inflammatory effects of the solution. /Hydrogen enriched saline/
Liu Y et al; BMC Gastroenterol 14: 12 (2014)
/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ Hydrogen has been reported to relieve damage in many disease models, and is a potential additive in drinking water to provide protective effects for patients as several clinical studies revealed. However, the absence of a dose-response relationship in the application of hydrogen is puzzling. We attempted to identify the dose-response relationship of hydrogen in alkaline electrolyzed drinking water through the aspirin induced gastric injury model. In this study, hydrogen-rich alkaline water was obtained by adding H2 to electrolyzed water at one atmosphere pressure. After 2 weeks of drinking, we detected the gastric mucosal damage together with MPO, MDA and 8-OHdG in rat aspirin induced gastric injury model. Hydrogen-dose dependent inhibition was observed in stomach mucosal. Under pH 8.5, 0.07, 0.22 and 0.84 ppm hydrogen exhibited a high correlation with inhibitory effects showed by erosion area, MPO activity and MDA content in the stomach. Gastric histology also demonstrated the inhibition of damage by hydrogen-rich alkaline water. However, 8-OHdG level in serum did not have significant hydrogen-dose dependent effect. pH 9.5 showed higher but not significant inhibitory response compared with pH 8.5. Hydrogen is effective in relieving the gastric injury induced by aspirin-HCl, and the inhibitory effect is dose-dependent. The reason behind this may be that hydrogen-rich water directly interacted with the target tissue, while the hydrogen concentration in blood was buffered by liver glycogen, evoking a suppressed dose-response effect. Drinking hydrogen-rich water may protect healthy individuals from gastric damage caused by oxidative stress. /Hydrogen water/
Xue J et al; BMC Complement Altern Med 14: 81 (2014)
/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ The prevalence of sleep apnea is very high in patients with heart failure (HF). The aims of this study were to investigate the influence of intermittent hypoxia (IH) on the failing heart and to evaluate the antioxidant effect of hydrogen gas. Normal male Syrian hamsters (n = 22) and cardiomyopathic (CM) hamsters (n = 33) were exposed to IH (repeated cycles of 1.5 min of 5% oxygen and 5 min of 21% oxygen for 8 hr during the daytime) or normoxia for 14 days. Hydrogen gas (3.05 vol/100 vol) was inhaled by some CM hamsters during hypoxia. IH increased the ratio of early diastolic mitral inflow velocity to mitral annulus velocity (E/e', 21.8 vs. 16.9) but did not affect the LV ejection fraction (EF) in normal Syrian hamsters. However, IH increased E/e' (29.4 vs. 21.5) and significantly decreased the EF (37.2 vs. 47.2%) in CM hamsters. IH also increased the cardiomyocyte cross-sectional area (672 vs. 443 sq um) and interstitial fibrosis (29.9 vs. 9.6%), along with elevation of oxidative stress and superoxide production in the left ventricular (LV) myocardium. Furthermore, IH significantly increased the expression of brain natriuretic peptide, beta-myosin heavy chain, c-fos, and c-jun mRNA in CM hamsters. Hydrogen gas inhalation significantly decreased both oxidative stress and embryonic gene expression, thus preserving cardiac function in CM hamsters. In conclusion, IH accelerated LV remodeling in CM hamsters, at least partly by increasing oxidative stress in the failing heart. These findings might explain the poor prognosis of patients with HF and sleep apnea.
Kato R et al; Am J Physiol Heart Circ Physiol 307 (11): H1626-33 (2014)
/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ Maternal inflammation is associated with spontaneous preterm birth and respiratory impairment among premature infants. Recently, molecular hydrogen (H2) has been reported to have a suppressive effect on oxidative stress and inflammation. The aim of this study was to evaluate the effects of H2 on fetal lung injury caused by maternal inflammation. Cell viability and the production of interleukin-6 (IL-6) and reactive oxygen species (ROS) were examined by treatment with lipopolysaccharide (LPS) contained in ordinal or H2-rich medium (HM) using a human lung epithelial cell line, A549. Pregnant Sprague Dawley rats were divided into three groups: Control, LPS, and HW + LPS groups. Rats were injected with phosphate-buffered saline (Control) or LPS intraperitoneally (LPS) on gestational day 19 and provided H2 water (HW) ad libitum for 24 hr before LPS injection (HW + LPS). Fetal lung samples were collected on day 20, and the levels of apoptosis, oxidative damage, IL-6, and vascular endothelial growth factor (VEGF) were evaluated using immunohistochemistry. The number of apoptotic cells, and levels of ROS and IL-6 were significantly increased by LPS treatment, and repressed following cultured with HM in A549 cells. In the rat models, the population positive for cleaved caspase-3, 8-hydroxy-2'-deoxyguanosine, IL-6, and VEGF was significantly increased in the LPS group compared with that observed in the Control group and significantly decreased in the HW + LPS group. In this study, LPS administration induced apoptosis and oxidative damage in fetal lung cells that was ameliorated by maternal H2 intake. Antenatal H2 administration may decrease the pulmonary mobility associated with inflammation in premature infants. /Hydrogen-rich medium/
Hattori Y et al; Free Radic Res 49 (8): 1026-37 (2015)
For more Non-Human Toxicity Excerpts (Complete) data for Hydrogen (16 total), please visit the HSDB record page.

14.2 Ecological Information

14.2.1 Natural Pollution Sources

... Hydrogen is the most abundant of all elements in the universe, and it is thought that the heavier elements were, and still are, being built from hydrogen and helium. It has been estimated that hydrogen makes up more than 90% of all the atoms or three quarters of the mass of the universe. It is found in the sun and most stars, and plays an important part in the proton-proton reaction and carbon-nitrogen cycle, which accounts for the energy of the sun and stars. It is thought that hydrogen is a major component of the planet Jupiter and that at some depth in the planet's interior the pressure is so great that solid hydrogen is converted into solid metallic hydrogen.
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 4-17
Occurrence in earth's atmosphere 0.00005% H2.
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 887
Hydrogen from natural sources consists of more than 99.8% protium. ...
Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980., p. 346

14.2.2 Probable Routes of Human Exposure

According to the 2016 TSCA Inventory Update Reporting data, nn reporting facilities estimate the number of persons reasonably likely to be exposed during the manufacturing, processing, or use of hydrogen in the United States may be as low as <10 workers and as high as <10,000 workers per plant; the data may be greatly underestimated due to confidential business information (CBI) or unknown values(1).
(1) US EPA; Chemical Data Reporting (CDR). Non-confidential 2012 Chemical Data Reporting information on chemical production and use in the United States. Available from, as of Jun 22, 2017: https://www.epa.gov/chemical-data-reporting

15 Associated Disorders and Diseases

Associated Occupational Diseases with Exposure to the Compound
Asphyxiation, simple [Category: Acute Poisoning]

16 Literature

16.1 Consolidated References

16.2 NLM Curated PubMed Citations

16.3 Thieme References

16.4 Wiley References

16.5 Chemical Co-Occurrences in Literature

16.6 Chemical-Gene Co-Occurrences in Literature

16.7 Chemical-Disease Co-Occurrences in Literature

17 Patents

17.1 Depositor-Supplied Patent Identifiers

17.2 WIPO PATENTSCOPE

17.3 Chemical Co-Occurrences in Patents

17.4 Chemical-Disease Co-Occurrences in Patents

17.5 Chemical-Gene Co-Occurrences in Patents

18 Interactions and Pathways

18.1 Protein Bound 3D Structures

18.2 Chemical-Target Interactions

18.3 Pathways

19 Taxonomy

Zebrafish Pathway Metabolite MetFrag Local CSV (Beta) | DOI:10.5281/zenodo.3457553

20 Classification

20.1 MeSH Tree

20.2 ChEBI Ontology

20.3 ChemIDplus

20.4 CAMEO Chemicals

20.5 UN GHS Classification

20.6 EPA CPDat Classification

20.7 NORMAN Suspect List Exchange Classification

20.8 EPA DSSTox Classification

20.9 EPA TSCA and CDR Classification

20.10 EPA Substance Registry Services Tree

20.11 MolGenie Organic Chemistry Ontology

21 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
    HYDROGEN, REFRIGERATED LIQUID (CRYOGENIC LIQUID)
    https://cameochemicals.noaa.gov/chemical/3606
    CAMEO Chemical Reactivity Classification
    https://cameochemicals.noaa.gov/browse/react
  3. 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/
  4. ChemIDplus
    ChemIDplus Chemical Information Classification
    https://pubchem.ncbi.nlm.nih.gov/source/ChemIDplus
  5. DHS Chemical Facility Anti-Terrorism Standards (CFATS) Chemicals of Interest
  6. DrugBank
    LICENSE
    Creative Common's Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/legalcode)
    https://www.drugbank.ca/legal/terms_of_use
  7. EPA Chemical Data Reporting (CDR)
    LICENSE
    The U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce these documents, or allow others to do so, for U.S. Government purposes. These documents may be freely distributed and used for non-commercial, scientific and educational purposes.
    https://www.epa.gov/web-policies-and-procedures/epa-disclaimers#copyright
  8. EPA Chemicals under the TSCA
    EPA TSCA Classification
    https://www.epa.gov/tsca-inventory
  9. EPA DSSTox
    CompTox Chemicals Dashboard Chemical Lists
    https://comptox.epa.gov/dashboard/chemical-lists/
  10. 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
  11. 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
  12. Hazardous Substances Data Bank (HSDB)
  13. 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
  14. ILO-WHO International Chemical Safety Cards (ICSCs)
  15. 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/
  16. NJDOH RTK Hazardous Substance List
  17. EU Food Improvement Agents
  18. Emergency Response Guidebook (ERG)
  19. 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
  20. ChEBI
  21. RRUFF Project
  22. ClinicalTrials.gov
    LICENSE
    The ClinicalTrials.gov data carry an international copyright outside the United States and its Territories or Possessions. Some ClinicalTrials.gov data may be subject to the copyright of third parties; you should consult these entities for any additional terms of use.
    https://clinicaltrials.gov/ct2/about-site/terms-conditions#Use
  23. 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
  24. 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
  25. ECI Group, LCSB, University of Luxembourg
    LICENSE
    Data: CC-BY 4.0; Code: Artistic-2.0
    https://creativecommons.org/licenses/by/4.0/
    Hydrogen
  26. EPA Chemical and Products Database (CPDat)
  27. Hazardous Chemical Information System (HCIS), Safe Work Australia
  28. NITE-CMC
  29. 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
  30. FooDB
    LICENSE
    FooDB 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 (FooDB) and the original publication.
    https://foodb.ca/about
  31. 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
  32. National Drug Code (NDC) Directory
    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
  33. NIPH Clinical Trials Search of Japan
  34. 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
  35. SpectraBase
  36. Pistoia Alliance Chemical Safety Library
    Nitrous oxide + Nitric oxide + Sodium + Hydrogen + Sodium formate + Toluene
    https://safescience.cas.org/
  37. PubChem Elements
  38. Rhea - Annotated Reactions Database
    LICENSE
    Rhea has chosen to apply the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/). This means that you are free to copy, distribute, display and make commercial use of the database in all legislations, provided you credit (cite) Rhea.
    https://www.rhea-db.org/help/license-disclaimer
  39. SpringerMaterials
  40. 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/
  41. Wikidata
  42. Wikipedia
  43. Wiley
  44. 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
  45. PubChem
  46. GHS Classification (UNECE)
  47. 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/
    NORMAN Suspect List Exchange Classification
    https://www.norman-network.com/nds/SLE/
  48. EPA Substance Registry Services
  49. MolGenie
    MolGenie Organic Chemistry Ontology
    https://github.com/MolGenie/ontology/
  50. PATENTSCOPE (WIPO)
CONTENTS