Material Safety Data Sheet: Hydrogen

Identification

Chemical Name: Hydrogen Synonyms: Dihydrogen, Molecular Hydrogen, H2 CAS Number: 1333-74-0 Recommended Use: Industrial gas, fuel, chemical synthesis, calibration gas Supplier/Manufacturer: Contact gas producer for details and emergency information Emergency Telephone: Reference local guidelines and emergency phone contacts for hazardous materials response UN Number: UN1049 (Compressed); UN1966 (Liquid)

Hazard Identification

Classification: Flammable gas, Category 1; Gases under pressure Signal Word: Danger Hazard Statements: Extremely flammable gas, May form explosive mixtures with air, May displace oxygen and cause rapid suffocation Pictograms: Flame, Gas cylinder Precautionary Statements: Keep away from ignition sources, No smoking, Secure cylinder in upright position, Use only outdoors or in a well-ventilated area, Do not breathe gas Other Hazards: In enclosed areas or confined spaces, can create risk of asphyxiation due to oxygen displacement; Vapors are lighter than air and rise rapidly

Composition / Information on Ingredients

Chemical Composition: 100% Hydrogen Molecular Formula: H2 Molecular Weight: 2.016 g/mol Impurities: May contain trace levels of oxygen, nitrogen, or moisture depending on grade and supplier; impurities may affect specific hazard or reactivity characteristics Exposure Limits: No specific limits for hydrogen, focus addresses oxygen displacement risks

First Aid Measures

Inhalation: Remove victim to fresh air, Restore or assist breathing if not breathing, Keep victim warm and at rest, Seek medical attention if symptoms of suffocation or disorientation persist Skin Contact: Not anticipated under normal conditions, For frostbite due to crude (liquid) hydrogen, flush with lukewarm water, Do not rub affected area Eye Contact: In the event of eye exposure to cold gas or liquid, flush immediately with plenty of lukewarm water and seek prompt medical attention Ingestion: Not applicable; hydrogen is a gas at room temperature Symptoms of Overexposure: Dizziness, headache, suffocation, nausea in low-oxygen environments, No specific toxicity documented under atmospheric conditions

Fire-Fighting Measures

Suitable Extinguishing Media: Non-combustible agents only, such as water spray (to cool containers), dry chemical, CO2 Unsuitable Extinguishing Media: Direct stream of water may scatter fire Specific Hazards: Containers may explode when heated, Rapid flame propagation possible, Invisible flame presents detection risks Protective Equipment for Firefighters: Full protective gear and self-contained breathing apparatus (SCBA), Evacuate area, Approach from upwind Special Instructions: Stop gas flow if safe, Cool fire-exposed cylinders with water spray, Avoid actions that may increase leaking

Accidental Release Measures

Personal Precautions: Evacuate area, Remove all ignition sources, Ensure adequate ventilation, Use non-sparking tools Protective Equipment: Appropriate respiratory protection in enclosed areas, Gloves and goggles for contact with liquid hydrogen Spill: Cease leak if safe, Remove sources of ignition, Ventilate area, Avoid breathing vapor Environmental Precautions: Prevent release to atmospheres in confined or poorly ventilated spaces, Alert local emergency responders Methods for Cleanup: Disperse gas with forced ventilation, Do not direct water onto leaking containers, Continue monitoring flammable gas levels

Handling and Storage

Handling: Use only in well-ventilated places, Ground/bond containers and equipment, Avoid contact with ignition sources, Do not smoke around hydrogen installations, Prevent accumulation of static electricity Storage: Store cylinders upright and secure, Protect from sunlight and temperature extremes, Isolate from oxidizers, Ensure proper identification of all containers, Store away from confined spaces Engineering Controls: Install hydrogen detectors and flame sensors where practical, Ensure emergency shut-off valves are accessible, Post suitable warning and hazard signage in areas with hydrogen pipelines or tanks

Exposure Controls and Personal Protection

Occupational Exposure Limits: OSHA, NIOSH, and ACGIH do not specify exposure limits for hydrogen gas Engineering Controls: Install ventilation systems, Oxygen monitoring recommended for enclosed or covered areas, Use explosion-proof electrical equipment Personal Protective Equipment: Safety glasses or chemical splash goggles, Flame-resistant gloves, Protective clothing if contact with cryogenic hydrogen is possible Respiratory Protection: Use positive pressure respiratory protection in case of accidental release or low-oxygen environments Hygiene Measures: Wash hands after handling gas and before eating, drinking, or smoking

Physical and Chemical Properties

Appearance: Colorless gas Odor: Odorless Odor threshold: Not applicable pH: Not applicable Melting Point: -259.2 °C (-434.6 °F) Boiling Point: -252.9 °C (-423.2 °F) Flash Point: Not applicable Flammability: Extremely flammable gas Explosion Limits: Flammable range in air 4% to 75% by volume Vapor Pressure: Not relevant at normal temperature Vapor Density: 0.07 (air = 1) Solubility: Slightly soluble in water Relative Density: 0.08988 g/L at 0°C and 1 atm Auto-ignition Temperature: 585 °C (1085 °F)

Stability and Reactivity

Chemical Stability: Stable under normal temperature and pressure Reactivity: Reacts violently with oxidizing agents, chlorine, fluorine, oxygen under certain conditions Conditions to Avoid: Flames, sparks, static discharge, high pressure, temperature variations Incompatible Materials: Oxidizing gases (oxygen, chlorine, fluorine, bromine) Hazardous Decomposition Products: Will not decompose under anticipated conditions but can react explosively with some chemical agents

Toxicological Information

Acute Toxicity: No significant toxicity, Asphyxiant risk due to displacement of oxygen Routes of Exposure: Inhalation only Symptoms of Overexposure: Headache, dizziness, nausea, unconsciousness, rapid suffocation in confined or poorly ventilated spaces Chronic Effects: No known chronic health effects, No evidence of mutagenicity, carcinogenicity, or reproductive toxicity found in available research Additional Data: Monitoring required in occupational settings where risk of asphyxiation is enhanced by confined space work

Ecological Information

Environmental Impact: Hydrogen released to atmosphere diffuses rapidly, No evidence for long-term toxicity or persistence in air, soil, or water Aquatic Toxicity: Not regarded as toxic to aquatic life Bioaccumulation: Will not bioaccumulate Mobility in Soil: Rapidly dissipates into atmosphere, Negligible impact on groundwater or soil structure Other Hazards: May contribute to fire or explosion risk in natural or built environments, Controlled releases recommended

Disposal Considerations

Disposal Methods: Release unused hydrogen to atmosphere in a safe, controlled, and well-ventilated area according to local, state, and federal regulations Product Disposal: Never attempt to dispose of residual gas in confined spaces; Consult with hazardous waste experts for bulk releases Container Disposal: Vent all residual gas before discarding cylinders, Mark containers as empty, Return to supplier or authorized dealer for safe handling and recycling Precautions: Ensure no risk of flame, spark, or heat source near the disposal method, Comply with all hazard communication and transportation requirements during shipping of empty or partially filled gas cylinders

Transport Information

UN Number: UN1049 for Compressed Hydrogen; UN1966 for Liquid Hydrogen Proper Shipping Name: Hydrogen, Compressed or Hydrogen, Refrigerated Liquid Transport Hazard Class: 2.1 (Flammable gas) Packing Group: Not applicable Labels Required: Flammable Gas Special Precautions: Transport only in authorized equipment, Cylinders must be upright and secured, Avoid physical damage and excessive heat, Document all shipments according to regulations

Regulatory Information

OSHA Status: Hydrogen classified as a hazardous chemical under OSHA Hazard Communication Standard EPA Regulations: Listed under Clean Air Act; Section 112 (R) for risk management DOT Classification: Flammable gas, Compressed or refrigerated liquid, Follows DOT regulations for transportation of hazardous materials SARA Title III: Covered under Extremely Hazardous Substances (EHS) for emergency planning and notification State and Local Regulations: Subject to additional state and local requirements, including fire department approval for storage and use in commercial settings Other Requirements: Consult national, regional, and site-specific regulations for full compliance in storage, use, and disposal