H2S Mix CH4

SECTION 2: Hazards identification

Warning Hazard Classification Gases Under Pressure Hazard Statements Contains gas under pressure; may explode if heated Toxic to aquatic life

Storage

Protect from sunlight. Store in well-ventilated place.

2.1 Classification of the substance or mixture

Gases Under Pressure Hazard Statements: Contains gas under pressure; may explode if heated Toxic to aquatic life Precautionary Statements Storage: Protect from sunlight. Store in well-ventilated place. Section 3: Composition/Information on Ingredients CAS # Concentration Hydrogen Sulfide 7783-06-4 10 ppm - 100 ppm Carbon Monoxide 630-08-0 50 ppm - 800 ppm Methane 74-82-8 1.45% - 2.5% Oxygen 7782-44-7 12% - 20.9% Nitrogen 7727-37-9 Balance Chemical Trade Names Substance Family Hydrogen HYDROGEN inorganic, gas HYDROGEN SULFIDE (H2S); DIHYDROGEN MONOSULFIDE; DIHYDROGEN Sulfide SULFIDE SULFIDE; HYDROSULFURIC ACID; SULFUR DIHYDRIDE; SULFURETED HYDROGEN; SULFUR HYDRIDE; STINK DAMP; SEWER GAS; RCRA U135; UN 1053; H2S Carbon CARBON inorganic, gas CARBON OXIDE; CARBON OXIDE (CO); UN 1016; CO Monoxide MONOXIDE Methane METHANE, hydrocarbons, FIRE DAMP; MARSH GAS; METHYL HYDRIDE; NATURAL GAS; METHANE; UN COMPRESSED GAS gas 1971; R50; CH4 Oxygen OXYGEN, inorganic, gas OXYGEN; DIOXYGEN; MOLECULAR OXYGEN; OXYGEN MOLECULE; PURE COMPRESSED GAS OXYGEN; UN 1072; O2 Nitrogen NITROGEN, inorganic, gas DIATOMIC NITROGEN; DINITROGEN; NITROGEN; NITROGEN-14; NITROGEN GAS; COMPRESSED GAS UN 1066; N2 Section 4: First Aid Measures Skin Contact Eye Contact Ingestion Inhalation Note to Physicians Hydrogen Wash skin with soap and water for Flush eyes with If a large If adverse effects occur, remove to For Sulfide at least 15 minutes while removing plenty of water for amount is uncontaminated area. Give artificial inhalation, contaminated clothing and shoes. at least 15 swallowed, get respiration if not breathing. If consider Get medical attention, if needed. minutes. Then get medical breathing is difficult, oxygen should oxygen. Thoroughly clean and dry immediate medical attention. be administered by qualified contaminated clothing and shoes attention. personnel. Get immediate medical before reuse. attention. Carbon Wash skin with soap and water for Flush eyes with If a large If adverse effects occur, remove to For Monoxide at least 15 minutes while removing plenty of water for amount is uncontaminated area. Give artificial inhalation, contaminated clothing and shoes. at least 15 swallowed, get respiration if not breathing. If consider Get medical attention, if needed. minutes. Then get medical breathing is difficult, oxygen should oxygen. Thoroughly clean and dry immediate medical attention. be administered by qualified contaminated clothing and shoes attention. personnel. Get immediate medical before reuse. attention. Methane Wash exposed skin with soap and Flush eyes with If a large If adverse effects occur, remove to For water. plenty of water. amount is uncontaminated area. Give artificial inhalation, swallowed, get respiration if not breathing. If consider medical breathing is difficult, oxygen should oxygen. attention. be administered by qualified personnel. Get immediate medical attention. Oxygen None expected Not likely route If adverse effects occur, remove to None of exposure uncontaminated area. Give artificial respiration if not breathing. Get immediate medical attention. Nitrogen Wash exposed skin with soap and Flush eyes with If a large If adverse effects occur, remove to For water. plenty of water. amount is uncontaminated area. Give artificial inhalation, swallowed, get respiration if not breathing. If consider medical breathing is difficult, oxygen should oxygen. attention. be administered by qualified personnel. Get immediate medical attention. Section 5: Fire Fighting Measures Suitable Extinguishing Media Products of Protection of Firefighters Combustion Suitable Extinguishing Media Products of Protection of Firefighters Combustion Hydrogen Let burn unless leak can be stopped Sulfur oxides  Any self-contained breathing apparatus with a full Sulfide immediately. Large fires: Use regular foam facepiece. or flood with fine water spray.  Protective material types: butyl rubber, polyvinyl chloride (PVC), neoprene Carbon Carbon dioxide, regular dry chemical Large Carbon dioxide  Any supplied-air respirator with full facepiece and Monoxide fires: Use regular foam or flood with fine operated in a pressure-demand or other positive- water spray. pressure mode in combination with a separate escape supply.  Any supplied-air respirator with full facepiece and operated in a pressure-demand or other positive- pressure mode in combination with a separate escape supply. Methane Carbon dioxide, regular dry chemical Large Carbon monoxide,  Respiratory protection may be needed for frequent fires: Use regular foam or flood with fine carbon dioxide, or heavy exposure. Any self-contained breathing water spray. water apparatus with a full facepiece.  Respiratory protection may be needed for frequent or heavy exposure. Any self-contained breathing apparatus with a full facepiece. Oxygen Non-flammable. Use extinguishing agent Oxides of burning  Respiratory protection may be needed for frequent appropriate for the material which is burning. material or heavy exposure. Use water in large quantities for fires  None involving oxygen. Nitrogen Non-flammable. Use suitable extinguishing Non-flammable  Respiratory protection may be needed for frequent media for surrounding fire. Cylinders may or heavy exposure. rupture or explode if exposed to heat. Section 6: Accidental Release Measures Personal Precautions Environmental Precautions Methods for Containment Hydrogen Keep unnecessary people away, isolate hazard area and Avoid heat, flames, sparks Stop leak if possible without personal Sulfide deny entry. Stay upwind and keep out of low areas. and other sources of ignition. risk. Remove sources of ignition. Ventilate closed spaces before entering. Evacuation Reduce vapors with water spray. Do radius: 150 feet. For tank, rail car or tank truck: 800 not get water directly on material. meters (1/2 mile). Do not touch spilled material. Carbon Keep unnecessary people away, isolate hazard area and Avoid heat, flames, sparks Stop leak if possible without personal Monoxide deny entry. Ventilate closed spaces before entering. and other sources of ignition. risk. Reduce vapors with water Keep out of water supplies spray. Remove sources of ignition. and sewers. Methane Keep unnecessary people away, isolate hazard area and Avoid heat, flames, sparks Stop leak if possible without personal deny entry. Ventilate closed spaces before entering. and other sources of ignition. risk. Reduce vapors with water spray. Remove sources of ignition. Oxygen Keep unnecessary people away, isolate hazard area and Avoid contact with Stop leak if possible without personal deny entry. Ventilate closed spaces before entering. combustible materials. risk. Nitrogen Keep unnecessary people away, isolate hazard area and No significant effects from Stop leak if possible without personal deny entry. Stay upwind and keep out of low areas. contamination expected. risk. Methods for Cleanup Other Information Hydrogen Collect runoff for disposal as potential hazardous Notify Local Emergency Planning Committee and State Emergency Sulfide waste. Dike for later disposal. Absorb with sand or Response Commission for release greater than or equal to RQ (U.S. SARA other non-combustible material. Add an alkaline Section 304). If release occurs in the U.S. and is reportable under material (lime, crushed limestone, sodium CERCLA Section 103, notify the National Response Center at (800)424- bicarbonate, or soda ash). 8802 (USA) or (202)426-2675 (USA). Carbon Stop leak, evacuate area. Wear protective equipment. Subject to California Safe Drinking Water and Toxic Enforcement Act of Monoxide 1986 (Proposition 65). Methane Not available Oxygen Stop leak and ventilate None Nitrogen N/A Section 7: Handling and Storage Handling Storage Handling Storage Hydrogen Store and handle in accordance with all current regulations and standards. Protect from Subject to handling regulations: U.S. Sulfide physical damage. Store outside or in a detached building. Store in a cool, dry place. OSHA 29 CFR 1910.119. Store in a well-ventilated area. Avoid contact with light. Grounding and bonding required. Subject to storage regulations: U.S. OSHA 29 CFR 1910.101. Notify State Emergency Response Commission for storage or use at amounts greater than or equal to the TPQ (U.S. EPA SARA Section 302). SARA Section 303 requires facilities storing a material with a TPQ to participate in local emergency response planning (U.S. EPA 40 CFR 355.30). Keep separated from incompatible substances. Carbon Keep separated from incompatible substances. Store and handle in accordance with all Monoxide current regulations and standards. Grounding and bonding required. Subject to storage regulations: U.S. OSHA 29 CFR 1910.101. Methane Store and handle in accordance with all current regulations and standards. Grounding Keep separated from incompatible and bonding required. Subject to storage regulations: U.S. OSHA 29 CFR 1910.101. substances. Oxygen Store and handle in accordance with all current regulations and standards. Subject to Keep separated from incompatible storage regulations: U.S. OSHA 29 CFR 1910.101. substances. Nitrogen Store and handle in accordance with all current regulations and standards. Subject to Keep separated from incompatible storage regulations: U.S. OSHA 29 CFR 1910.101. substances. Section 8: Exposure Controls/Personal Protection Exposure Guidelines Hydrogen HYDROGEN SULFIDE: 20 ppm OSHA ceiling 50 ppm OSHA peak 10 minute(s) (once if no other measurable exposure occurs) 10 Sulfide ppm (14 mg/m3) OSHA TWA (vacated by 58 FR 35338, June 30, 1993) 15 ppm (21 mg/m3) OSHA STEL (vacated by 58 FR 35338, June 30, 1993) 10 ppm ACGIH TWA 15 ppm ACGIH STEL 10 ppm (15 mg/m3) NIOSH recommended ceiling 10 minute(s) TLV-TWA: 1ppm Upper respiratory irritation (ACGIH) Carbon CARBON MONOXIDE: 50 ppm (55 mg/m3) OSHA TWA 35 ppm (40 mg/m3) OSHA TWA (vacated by 58 FR 35338, June 30, Monoxide 1993) 200 ppm (229 mg/m3) OSHA ceiling (vacated by 58 FR 35338, June 30, 1993) 25 ppm ACGIH TWA 35 ppm (40 mg/m3) NIOSH recommended TWA 10 hour(s) 200 ppm (229 mg/m3) NIOSH recommended ceiling Methane METHANE, COMPRESSED GAS: ALIPHATIC HYDROCARBON GASES ALKANE (C1-C4): 1000 ppm ACGIH TWA METHANE: No occupational exposure limits established. ALIPHATIC HYDROCARBON GASES ALKANE (C1-C4): 1000 ppm ACGIH TWA Oxygen OXYGEN, COMPRESSED GAS: No occupational exposure limits established. Nitrogen NITROGEN, COMPRESSED GAS: NITROGEN: ACGIH (simple asphyxiant) Engineering Controls Handle only in fully enclosed systems. Eye Protection Skin Protection Respiratory Protection Hydrogen Wear splash resistant safety goggles with a face Wear appropriate Any self-contained breathing apparatus with a full Sulfide shield. Provide an emergency eye wash fountain chemical resistant facepiece. and quick drench shower in the immediate work clothing. area. Carbon Eye protection not required, but recommended. Protective clothing Any supplied-air respirator with full facepiece and Monoxide is not required. operated in a pressure-demand or other positive- pressure mode in combination with a separate escape supply. Methane Eye protection not required, but recommended. Protective clothing Respiratory protection may be needed for frequent is not required. or heavy exposure. Any self-contained breathing apparatus with a full facepiece. Oxygen Eye protection not required, but recommended. Protective clothing Respiratory protection may be needed for frequent is not required. or heavy exposure. Nitrogen Eye protection not required, but recommended. Protective clothing Respiratory protection may be needed for frequent is not required. or heavy exposure. General Hygiene considerations  Avoid breathing vapor or mist  Avoid contact with eyes and skin  Wash thoroughly after handling and before eating or drinking Section 9: Physical and Chemical Properties Physical State Appearance Color Change in Appearance Physical Form Odor Taste Hydrogen Sulfide Gas Colorless N/A Gas Rotten egg odor N/A Carbon Monoxide Gas Colorless N/A Gas Odorless Tasteless Methane Gas Colorless N/A Gas, liquid Odorless Tasteless Oxygen Gas Clear Colorless N/A Gas Odorless Tasteless Nitrogen Gas Clear Colorless N/A Gas Odorless Tasteless Flash Point Flammability Partition Coefficient Autoignition Upper Explosive Lower Explosive Temperature Limits Hydrogen Flammable Not available 500 F (260 C) 44-46% 4.0-4.3% Sulfide Carbon Flammable Not available 1479.11 (log = 3.17) 1128-1202 F (609- 0.74 12.0-12.5% Monoxide (estimated from water 650 C) solubility) Methane -369 F (-223 Not available 724.44 (log = 2.87) 999 F (537 C) 15% 5% C) (estimated from water solubility) Oxygen Not Not available Nonflammable flammable Nitrogen Not Not available Nonflammable flammable Boiling Freezing Vapor Specific Water pH Odor Evaporation Viscosity Point Pressure Density Gravity Solubility Threshold Rate Hydrogen -78 to - -123 F (- 15200 1.2 1.192 2.58-2.9% 4.5-<7 0.13 ppm Not 0.0128 Sulfide 77 F (- 86 C) mmHg @ (Air=1) @ 20 C (saturated applicable cP @ 25 61 to - 25 C solution) C 60.3 C) Carbon -312.7 -326 F (- 760 mmHg 0.968 Not 2.3% @ Not 0.01657 Monoxide F (- 199 C) @ -191 C (Air=1) applicable 20 C applicable available applicable cP @ 0 C 191.5 gas; cannot C) be liquefied at room temperature Methane -260 F -297 F (- 760 mmHg 0.555 Not 3.5% @ Not 0.01118 (-162 183 C) @ -161 C (Air=1) applicable 17 C applicable available applicable cP @ 27 C) C Oxygen -297 F -360 F (- 760 mmHg 1.1 Not 3.2% @ Not 0.02075 (-183 218 C) @ -183 C (Air=1) applicable 25 C applicable available applicable cP @ 25 C) C Nitrogen -321 F -346 F (- 760 mmHg 0.967 Not 1.6% @ Not 0.01787 (-196 210 C) @ -196 C (Air=1) applicable 20 C applicable available applicable cP @ 27 C) C Molecular Density Weight per Volatility by Volatility Solvent Solubility Weight Formula Gallon Volume Hydrogen 34.08 H2-S 1.539 g/L Not Not available Not Soluble: Carbon disulfide, alcohol, Sulfide @ 0 C available applicable ether, glycerol, gasolines, kerosene, crude oil, alkali solutions Carbon 28.01 C-O 1.250 g/L Not 100% Not Soluble: Alcohol, benzene, acetic Monoxide @ 0 C available applicable acid, ethyl acetate, chloroform, cuprous chloride solutions Methane 16.04 C-H4 0.717 g/L Not Soluble: Alcohol, ether, benzene, @ 0 C available applicable organic solvents Oxygen 31.9988 O2 1.309 g/L Not Soluble: Alcohol @ 25 C available applicable Nitrogen 28.0134 N2 1.2506 g/L Not 100% 1 Soluble: Liquid ammonia available Section 10: Stability and Reactivity Stability Conditions to Avoid Incompatible Materials Hydrogen Stable at normal Combustible materials, metals, oxidizing materials, halogens, metal Sulfide temperatures and oxides, metal salts, bases, rust, oxidants, oxygen, copper powder, pressure. acetaldehyde, silver fulminate Carbon Stable at normal Oxidizing materials, halogens, metal oxides, metals, combustible Monoxide temperatures and materials, lithium pressure. Methane Stable at normal Halogens, oxidizing materials, combustible materials temperatures and pressure. Oxygen Stable at normal Combustible materials, halo carbons, metals, bases, reducing agents, temperatures and amines, metal salts, oxidizing materials, alkaline earth and alkali metals pressure. Nitrogen Stable at normal Metals, oxidizing materials temperatures and pressure. Hazardous Decomposition Products Possibility of Hazardous Reactions Hydrogen Sulfide Oxides of sulfur Will not polymerize. Carbon Monoxide Oxides of carbon Will not polymerize. Methane Oxides of carbon Will not polymerize. Oxygen Miscellaneous decomposition products Will not polymerize. Nitrogen Oxides of nitrogen Will not polymerize. Section 11: Toxicology Information Acute Effects Oral LD50 Dermal LD50 Inhalation Hydrogen 444 ppm Irritation 0.000125 Irritation, lack of sense of smell, sensitivity to light, nausea, vomiting, difficulty breathing, Sulfide inhalation-rat ppm/5 hour(s) headache, drowsiness, dizziness, disorientation, tremors, visual disturbances, LC50 eyes-human suffocation, lung congestion, internal bleeding, heart damage, nerve damage, brain damage, coma, death Carbon LC50 Inhalation Not available Changes in body temperature, changes in blood pressure, nausea, vomiting, chest pain, Monoxide Gas. Rat 1807 difficulty breathing, irregular heartbeat, headache, drowsiness, dizziness, disorientation, ppm 4 hours hallucinations, pain in extremities, tremors, loss of coordination, hearing loss, visual disturbances, eye damage, suffocation, blood disorders, convulsions, coma Methane Not available Nausea, vomiting, difficulty breathing, irregular heartbeat, headache, drowsiness, fatigue, dizziness, disorientation, mood swings, tingling sensation, loss of coordination, suffocation, convulsions, unconsciousness, coma Oxygen Not established Irritation, changes in body temperature, nausea, difficulty breathing, irregular heartbeat, dizziness, disorientation, hallucinations, mood swings, pain in extremities, tremors, lung congestion, convulsions Nitrogen Not available Nausea, vomiting, difficulty breathing, headache, drowsiness, dizziness, tingling sensation, loss of coordination, convulsions, coma Eye Irritation Skin Irritation Sensitization Hydrogen Irritation, sensitivity to light, visual Irritation liquid: frostbite Harmful if inhaled, respiratory tract irritation, skin Sulfide disturbances irritation, eye irritation, blood damage Carbon No information on significant adverse No information on significant Blood damage, suffocation Monoxide effects adverse effects Methane No information on significant adverse No information on significant Difficulty breathing effects adverse effects Oxygen No information on significant adverse No information on significant No significant target effects reported. effects adverse effects Nitrogen Contact with rapidly expanding gas may No information on significant Difficulty breathing cause burns or frostbite adverse effects Chronic Effects Carcinogenicity Mutagenicity Reproductive Effects Developmental Effects Hydrogen Sulfide Not available Available. No data Carcinogenicity Mutagenicity Reproductive Effects Developmental Effects Carbon Monoxide Not available Available. No data Methane Not available No data Oxygen Not known. Available. No data Nitrogen Not hazardous Not available No data Section 12: Ecological Information Fate and Transport Eco toxicity Persistence / Bioaccumulation / Mobility in Degradability Accumulation Environment Hydrogen Fish toxicity: Acute LC50 7 ug/L Fresh water Highly toxic to aquatic life. Not available Sulfide Fish - Fathead minnow - Pimephales promelas - FRY 96 hours; 14.9 ug/L 96 hour(s) LC50 (Mortality) Fathead minnow (Pimeph Invertibrate toxicity: 9730 ug/L 1.5 hour(s) (Mortality) Mediterranean mussel (Mytilus galloprovincialis) Algal toxicity: Not available Phyto toxicity: Not available Other toxicity: Not available Carbon Fish toxicity: 75000 ug/L 1 day(s) LC100 Relatively non-persistent Not available Not expected to leach Monoxide (Mortality) Orangespotted sunfish (Lepomis in the environment. Highly through the soil or the humilis) volatile from water. sediment. Invertibrate toxicity: Not available Algal toxicity: Not available Phyto toxicity: Not available Other toxicity: Not available Methane Fish toxicity: Not available Relatively non-persistent Accumulates very little in Not expected to leach Invertibrate toxicity: Not available in the environment. the bodies of living through the soil or the Algal toxicity: Not available Moderately volatile from organisms. sediment. Phyto toxicity: Not available water. Other toxicity: Not available Oxygen Fish toxicity: Not available Not available Low bioaccumulation Not available Invertibrate toxicity: Not available Algal toxicity: Not available Phyto toxicity: Not available Other toxicity: Not available Nitrogen Fish toxicity: Not available Not available Invertibrate toxicity: Not available Algal toxicity: Not available Phyto toxicity: Not available Other toxicity: Not available Section 13: Disposal Considerations Hydrogen Dispose in accordance with all applicable regulations. Subject to disposal regulations: U.S. EPA 40 CFR 262. Hazardous Sulfide Waste Number(s): U135. Carbon Dispose in accordance with all applicable regulations. Subject to disposal regulations: U.S. EPA 40 CFR 262. Hazardous Monoxide Waste Number(s): D001. Methane Dispose in accordance with all applicable regulations. Subject to disposal regulations: U.S. EPA 40 CFR 262. Hazardous Waste Number(s): D001. Oxygen Dispose in accordance with all applicable regulations. Subject to disposal regulations: U.S. EPA 40 CFR 262. Hazardous Waste Number(s): D001. Nitrogen Dispose in accordance with all applicable regulations. Section 14: Transportation Information U.S. DOT 49 CFR 172.101 DOT Information For This Mixture Shipping Name Compressed gas, n.o.s. (Nitrogen, Oxygen) UN Number UN1956 Hazard Class 2.2 Hazard Information Non-Flammable Gas Individual Component Information Proper ID Hazard Packing Labeling Passenger Cargo Aircraft Additional Shipping Number Class or Group Requirements Aircraft or Only Quantity Shipping Name Division Railcar Quantity Limitations Description Limitations Hydrogen UN1053 2.3 Not 2.3; 2.1 Forbidden Toxic- Sulfide sulfide applicable Inhalation Hazard Zone B Carbon UN1016 2.3 Not 2.3; 2.1 Forbidden 25 kg Toxic- Monoxide monoxide, applicable Inhalation compressed Hazard Zone D Methane Methane, UN1971 2.1 Not 2.1 Forbidden 150 kg N/A compressed applicable Oxygen Oxygen, UN1072 2.2 Not 2.2; 5.1 75 kg or L 150 kg N/A compressed available Nitrogen Nitrogen, UN1066 2.2 Not 2.2 75 kg or L 150 kg N/A compressed applicable Canadian Transportation of Dangerous Goods Shipping Name UN Number Class Packing Group / Risk Group Hydrogen Sulfide HYDROGEN SULFIDE; or HYDROGEN SULPHIDE UN1053 2.3; 2.1 Not applicable Carbon Monoxide Carbon monoxide, compressed UN1016 2.3; 2.1 Not applicable Methane Methane, compressed UN1971 2.1 Not applicable Oxygen Oxygen, compressed UN1072 2.2; 5.1 Not applicable Nitrogen Nitrogen, compressed UN1066 2.2 Not applicable Section 15: Regulatory Information U.S. Regulations CERCLA Sections SARA 355.30 SARA 355.40 Hydrogen Sulfide 100 LBS RQ 500 LBS TPQ 100 LBS RQ Carbon Monoxide Not regulated. Methane Not regulated. Oxygen Not regulated. Nitrogen Not regulated. SARA 370.21 Acute Chronic Fire Reactive Sudden Release Hydrogen Sulfide Yes No Yes No Yes Carbon Monoxide Yes No Yes No Yes Methane Yes No Yes No Yes Oxygen No Yes No Yes Nitrogen Yes No Yes SARA 372.65 Hydrogen Sulfide HYDROGEN SULFIDE: Administrative stay issued Aug. 22, 1994 Carbon Monoxide Not regulated. Methane Not regulated. Oxygen Not regulated. Nitrogen Not regulated. OSHA Process Safety Hydrogen Sulfide 1500 LBS TQ Carbon Monoxide Not regulated. Methane Not regulated. Oxygen Not regulated. Nitrogen Not regulated. State Regulations CA Proposition 65 Hydrogen Sulfide Not regulated. Carbon Monoxide Known to the state of California to cause the following: Carbon monoxide Developmental toxicity (Jul 01, 1989) Methane Not regulated. Oxygen Not regulated. Nitrogen Not regulated. Canadian Regulations WHMIS Classification Hydrogen Sulfide A, B1, D1A, D2B. Carbon Monoxide A, B1, D1A, D2A. Methane A, B1 Oxygen A,C Nitrogen A National Inventory Status US Inventory (TSCA) TSCA 12b Export Notification Canada Inventory (DSL/NDSL) Hydrogen Sulfide Listed on inventory. Not listed. Listed on inventory. Carbon Monoxide Listed on inventory. Not listed. Listed on inventory. Methane Listed on inventory. Not listed. Listed on inventory. Oxygen Listed on inventory. Not listed. Not determined. Nitrogen Listed on inventory. Not listed. Listed on inventory. Section 16: Other Information NFPA Rating Hydrogen Sulfide HEALTH=4 FIRE=4 REACTIVITY=0 Carbon Monoxide HEALTH=3 FIRE=4 REACTIVITY=0 Methane HEALTH=1 FIRE=4 REACTIVITY=0 Oxygen HEALTH=0 FIRE=0 REACTIVITY=0 Nitrogen HEALTH=1 FIRE=0 REACTIVITY=0 0 = minimal hazard, 1 = slight hazard, 2 = moderate hazard, 3 = severe hazard, 4 = extreme hazard