Product Name: Hydrogen
Chemical Formula: H2
Molecular Weight: 2.016 g/mol
Synonyms: Dihydrogen, Molecular Hydrogen
CAS Number: 1333-74-0
Recommended Use: Fuel, industrial processes, welding, chemical manufacturing, electronics
Restrictions on Use: Consumer applications that lack controlled environments and trained personnel
Supplier/Manufacturer: Listed by major specialty gases providers worldwide
Emergency Contact: Refer to national chemical emergency hotlines and supplier-specific numbers
Hazard Classification: Flammable gas, category 1; Simple asphyxiant
Pictograms: Flame, Gas cylinder
Signal Word: Danger
Hazard Statements: Extremely flammable gas; Contains gas under pressure; May explode if heated; Displaces oxygen and can cause suffocation
Precautionary Statements: Keep away from sparks, open flames, heat; No smoking around storage or during handling; Use non-sparking tools; Ventilate work area; Avoid confined spaces
Physical Hazards: Gas expands rapidly if uncontrolled; Containers may rupture under fire exposure
Health Hazards: Inhalation causes dizziness and asphyxiation in enclosed spaces; Low concentrations can quickly result in loss of consciousness
Hydrogen: 100%
Impurities: Trace quantities of oxygen, water vapor, or hydrocarbons, generally less than 5 ppm
Other Ingredients: Not present in significant or hazardous amounts
Purities Offered: Standard industrial, ultra high-purity, research grade
Inhalation: Remove person to fresh air as soon as possible; call emergency medical services if breathing is difficult; provide oxygen if available
Skin Contact: No direct hazard in gaseous form; for liquefied hydrogen, treat frostbite by soaking affected areas in lukewarm water, do not rub, seek medical attention
Eye Contact: For exposure to cold vapors, rinse carefully with water, avoid using hot water, get medical help
Ingestion: Not considered a route of exposure due to physical state
Symptoms of Exposure: Rapid onset of headache, dizziness, confusion, numbness, unconsciousness in unventilated spaces
Flammability: Extremely high; most flammable of all gases
Auto-Ignition Temperature: 500°C (932°F)
Lower Explosion Limit: 4% by volume in air
Upper Explosion Limit: 75% by volume in air
Suitable Extinguishing Media: Water spray to cool containers, dry chemical, or CO2; shut off leak if safe
Precautions for Firefighters: Wear self-contained breathing gear and full protective clothing; approach from upwind; hydrogen flame is nearly invisible in daylight
Unusual Hazards: Containers may rupture or rocket in heat; gas can migrate and ignite at distance if released
Personal Precautions: Evacuate area; limit access; eliminate ignition sources; stop leak only by trained personnel with protective gear
Protective Equipment: Use explosion-proof equipment and grounded tools
Spill Procedures: Allow gas to vent to open air away from buildings and people; ventilate enclosed spaces rapidly
Environmental Precautions: Prevent escaping gas from entering sewers, basements, or confined locations where explosive mixtures can form
Cleanup: Never re-enter a spill area unless atmospheric monitoring shows safe oxygen levels and absence of hydrogen
Safe Handling: Ground and bond cylinders; handle with approved regulators and connections; never drop or drag cylinders
Technical Measures: Use leak-checking systems with hydrogen detectors; ventilate well, especially in confined spaces
Storage Conditions: Store in upright position; secure cylinders; keep away from heat, flames, and oxidizers including oxygen and chlorine
Incompatibilities: Avoid contact with halogens, oxidizers, and air under pressure; avoid exposure to static discharge
Safe Practices: Train staff on emergency procedures for leaks or fire; inspect equipment frequently for leaks or wear
Occupational Exposure Limits: No established OSHA PEL; asphyxiant in high concentrations
Engineering Controls: Ventilation systems for all storage and use areas; hydrogen detectors and alarms
Respiratory Protection: Use supplied-air respirator in oxygen-deficient or unknown conditions
Skin Protection: Standard work clothes for gaseous hydrogen; cryogenic gloves for liquid hydrogen
Eye Protection: Safety goggles or face shield especially for cryogenic operations
Personal Hygiene: Wash hands after handling containers or gas distribution equipment; avoid touching face or eyes when around release areas
Appearance: Colorless, odorless gas
Odor: None
Melting Point: -259°C (-434°F)
Boiling Point: -253°C (-423°F)
Flash Point: Not applicable (gas)
Vapor Pressure: Not applicable at room temperature (supplied in pressurized containers)
Solubility: Slightly soluble in water
Density: 0.08375 kg/m3 (gas at 0°C, 1 atm)
Relative Vapor Density: 0.069 (air = 1)
Critical Temperature: -240°C
Evaporation Rate: Rapid for liquid or solid forms
Chemical Stability: Stable under normal conditions without impurities
Reactivity: Readily reacts with oxygen in air to form water vapor, releases significant heat
Dangerous Reactions: Violent reaction with oxidizing agents; forms explosive mixtures with air and halogens
Polymerization: Will not occur
Conditions to Avoid: Heat, flames, sparks, static discharge, pressure build-up, strong oxidizers
Acute Toxicity: Not toxic; acts as simple asphyxiant by displacing oxygen
Chronic Effects: No evidence of chronic toxicity or carcinogenicity reported
Routes of Entry: Inhalation is primary concern, especially in unventilated spaces
Symptoms: Rapid oxygen displacement can cause loss of consciousness, suffocation, death in minutes if not evacuated
Medical Conditions Aggravated: Persons with respiratory or cardiac conditions face greater risk in case of oxygen deficiency
Other Data: Hydrogen by itself does not produce delayed or cumulative toxic effects
Environmental Impact: Hydrogen released to atmosphere quickly disperses and rises due to low density
Global Warming Potential: Zero direct impact; does not deplete ozone
Bioaccumulation: Not applicable; does not bioaccumulate in living organisms
Ecotoxicity: Safe for soil and water in small accidental releases; main concern remains explosion risk, not environmental persistence
Other Effects: May contribute indirectly to atmospheric photochemistry by influencing the fate of other pollutants
Waste Treatment: Hydrogen wastes must be safely vented to atmosphere in well-ventilated outdoor areas away from sources of ignition
Container Disposal: Empty gas cylinders through proper venting, depressurize, label clearly as “Empty,” and return to supplier
Precautions: Do not attempt to dispose of significant quantities without trained personnel and approved equipment
Regulations: Disposal procedures must meet federal, state, and local requirements for hazardous gases
DOT Classification: Compressed gas, flammable, UN 1049
Hazard Class: 2.1 (Flammable Gas)
Labels Required: Class 2.1—Flammable Gas
Packing Group: Not assigned
Special Precautions: Use approved cylinder trucks or carriers; secure cylinders to prevent movement during transport; segregate from oxidizers and sources of ignition
International Transport: IATA/ICAO and IMDG regulations require similar markings and safe handling
OSHA Hazard Communication: Classified as hazardous due to flammability and asphyxiation risk
EPA Clean Air Act: Not listed as an ozone-depleting substance; regulated due to potential fire/explosion risk
SARA Title III: Subject to Emergency Planning and Community Right-to-Know reporting requirements for threshold planning quantity
TSCA Status: Listed
WHMIS (Canada): Class A (Compressed Gas), Class B1 (Flammable Gas)
Other Regulatory Listings: Covered by national/international chemical safety and transport laws, including EU REACH and GHS standards
