Hydrogen Sulfide Material Safety Data Sheet (MSDS)

Identification

Product Name: Hydrogen Sulfide
Chemical Formula: H₂S
Synonyms: Dihydrogen sulfide, Hydrosulfuric acid, Sewer gas
CAS Number: 7783-06-4
Recommended Use: Used in chemical manufacturing, petroleum refining, and as an analytical reagent
Manufacturer: Typically, large chemical suppliers and industrial manufacturers handle hydrogen sulfide due to the hazards involved
Contact Information: Emergency phone numbers usually appear on commercial MSDS documents and should be accessible at job sites

Hazard Identification

Classification: Flammable gas, Toxic gas, Acute inhalation hazard
GHS Signal Word: Danger
Hazard Statements: Extremely flammable, Fatal if inhaled, Causes severe eye and respiratory irritation
Routes of Exposure: Inhalation most dangerous, can also be absorbed through skin
Symptoms of Exposure: Headache, dizziness, nausea, coughing, loss of consciousness, respiratory irritation, long term exposure can damage central nervous system
OSHA Hazard Classification: Acute toxicity, specific target organ toxicity, environmental hazard

Composition / Information on Ingredients

Chemical Identity: Hydrogen Sulfide (H₂S)
Concentration: Usually supplied as a pure gas, >99%
Impurities: Commercial grades may contain small amounts of water vapor or other sulfur compounds
Other Components: No additives in standard cylinders

First Aid Measures

Inhalation: Remove person to fresh air immediately, avoid self-exposure, call for emergency medical help, administer artificial respiration if breathing has stopped, oxygen if available
Skin Contact: Remove contaminated clothing, rinse skin thoroughly with soap and plenty of water
Eye Contact: Flush eyes with large amounts of water for at least 15 minutes, lift eyelids occasionally, seek urgent medical attention
Ingestion: Not considered a likely route due to gaseous state, in case of suspected ingestion seek immediate medical aid
Emergency Notes: Rapid onset of respiratory paralysis possible, rapid evacuation from contaminated area essential, rescuer protection required

Fire-Fighting Measures

Suitable Extinguishing Media: Dry chemical powder, carbon dioxide, water spray (do not use direct water stream), foam
Fire Hazards: Extremely flammable, forms explosive mixtures with air, sensitive to static discharge
Explosion Limits: Lower Explosion Limit: about 4.3% (volume in air); Upper Limit: about 45%
Hazardous Combustion Products: Sulfur dioxide, sulfur oxides
Protective Equipment for Firefighters: Use full protective gear and self-contained breathing apparatus
Specific Hazards: Leaking gas may accumulate in low-lying areas, gas is heavier than air, avoid confined spaces

Accidental Release Measures

Personal Precautions: Wear positive pressure self-contained breathing apparatus and full protective clothing, evacuate all non-essential personnel
Environmental Precautions: Prevent release into sewers and waterways, vent to atmosphere only in well-ventilated areas, authorities must be notified if large quantities released
Cleanup Methods: Isolate area, stop leak if safe to do so, use water spray to reduce vapors but avoid spraying directly on gas, ventilate area thoroughly
Emergency Procedures: Initiate company emergency response protocol, keep ignition sources away, prevent further access until decontamination complete

Handling and Storage

Handling: Work in well-ventilated areas or fume hoods, use leak-proof equipment, ground all containers and transfer equipment to suppress static, avoid all contact with oxidizers and acids, no smoking or open flames, train personnel on gas properties and emergency response
Storage Conditions: Store in tightly closed, approved gas cylinders, keep in cool, dry, well-ventilated, fireproof location, away from incompatible materials like strong oxidizers, store cylinder upright, secure to prevent tipping, label containers clearly, check regularly for signs of wear or damage
Special Handling Advice: Never use tools or connections that cause sparks, always use proper regulators and check hose integrity before use, restrict access to trained staff only

Exposure Controls and Personal Protection

Occupational Exposure Limits: OSHA PEL: 20 ppm (ceiling), NIOSH REL: 10 ppm (10-minute ceiling), ACGIH TLV: 1 ppm TWA, 5 ppm STEL
Engineering Controls: Exhaust ventilation, gas detection monitors, leak detection systems, emergency shut-off valves
Respiratory Protection: Positive pressure air-supplied respirators for emergencies, no reliance on cartridge respirators in concentrations above exposure limits
Skin Protection: Chemical resistant gloves, flame-resistant antistatic clothing
Eye Protection: Safety goggles, face shield
Hygiene Measures: Wash hands and face thoroughly after handling, avoid eating or drinking in the work area, remove contaminated clothing and wash before reuse

Physical and Chemical Properties

Appearance: Colorless gas
Odor: Characteristic rotten egg smell, odor threshold around 0.01–1.5 ppm, olfactory fatigue occurs at higher exposures
Boiling Point: -60 °C
Melting Point: -85.5 °C
Vapor Pressure: 1740 mm Hg at 20 °C
Solubility: Moderately soluble in water, more soluble in cold water
Density: 1.363 g/L at 0 °C, heavier than air
pH: Forms weak acid in water
Flash Point: -82 °C (closed cup)
Autoignition Temperature: 260 °C
Flammability: Easily ignited, explosive mixtures with air

Stability and Reactivity

Stability: Under normal temperatures and pressures, stable in closed containers
Hazardous Reactions: Reacts violently with oxidizers, metals, and strong acids, may cause pressure buildup in containers
Conditions to Avoid: Heat, flame, sparks, high temperatures, contact with oxidizers, confined spaces
Hazardous Decomposition Products: Sulfur oxides, hydrogen gas
Polymerization: Will not occur

Toxicological Information

Acute Toxicity: Highly toxic, lowest lethal concentration reported: around 500 ppm for 30 minutes (human), 700 ppm causes loss of consciousness rapidly
Chronic Effects: Repeated exposures can cause headaches, poor memory, olfactory fatigue, lung damage
Routes of Exposure: Inhalation is the major route, minor absorption through skin possible
Symptoms: Immediate irritation of eyes, nose, and throat, higher concentrations depress the central nervous system, respiratory paralysis at very high concentrations
Carcinogenicity: Not classified as carcinogenic by IARC, NTP, OSHA
Mutagenicity/Reproductive Toxicity: No definitive evidence from animal or human studies, but long-term high level exposure discouraged

Ecological Information

Ecotoxicity: Highly toxic to aquatic life, high concentrations can cause fish kills
Mobility in Environment: Easily evaporates, can contaminate air rapidly, water-soluble but can dissipate
Persistence and Degradation: Breaks down in air over time, oxidizes to sulfate, can persist in water under low oxygen conditions
Bioaccumulation: Not likely; does not build up in living tissues
Aquatic Toxicity: LC50 (fish): 0.016–1.1 mg/L (acute)

Disposal Considerations

Disposal Methods: Release only in accordance with local air quality regulations, burnt in approved flares, consult professional hazardous waste disposal contractors, avoid direct discharge to environment
Container Disposal: Decontaminate empty cylinders before return, do not puncture or incinerate non-empty containers, follow supplier return protocol
Precautions: Always advise authorized disposal firms of the hazardous nature of the gas and risks to handlers

Transport Information

UN Number: UN1053
Proper Shipping Name: Hydrogen sulfide, compressed
Hazard Class: 2.3 (Toxic gases), 2.1 (Flammable gases)
Packing Group: Not applicable for gases
Labels Required: Toxic Gas, Flammable Gas
Special Transport Precautions: Ship in approved gas cylinders, secure upright, do not transport with oxidizers, keep away from sources of ignition
Regulatory Transportation Tools: Check DOT, IATA, and IMO guidelines, restricted routes may apply

Regulatory Information

OSHA: Listed as hazardous substance, strict exposure limits
TSCA: Listed on Toxic Substances Control Act Inventory
SARA Title III (EPCRA): Listed as an extremely hazardous substance, Section 302 and 304, requires reporting for releases above threshold quantities
RCRA: Classified as hazardous waste if discarded, unique EPA waste number
State Regulations: Individual states may have stricter controls, California Proposition 65 warnings may apply
International: Covered by international treaties on shipment of hazardous materials, European REACH registration not required for pure gases but subject to workplace exposure monitoring