| GHS classification | DangerH220: Extremely flammable gas [Danger Flammable gases]P203, P210, P222, P280, P377, P381, and P403 (click each P-code to see the statement)H220 (100%): Extremely flammable gas [Danger Flammable gases]P203, P210, P222, P280, P282, P336+P317, P377, P381, P403, and P410+P403 (click each P-code to see the statement) |
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| Regulatory information | Chemical: MethaneMethane is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of Methane are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)Status: Active Update: 23-03-2023 https://echa.europa.eu/registration-dossier/-/registered-dossier/14250Methane or natural gas but excluding refrigerated liquid methane or natural gas: HSNO Approval: HSR001005 Approved with controlsThe New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.) |
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| Other safety information | IMAP assessments - Methane: Human health tier I assessment |
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| DOT label | Flammable Gas |
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| Fire hazards | Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]:Special Hazards of Combustion Products: None (USCG, 1999)· EXTREMELY FLAMMABLE. |
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| Fire potential | Very dangerous fire and explosion hazard when exposed to heat or flame.Flammable in the presence of an oxidizing gas (eg air), a source of ignition, and when the concentration of the gas is between the lower and upper explosive limits. Keep away from heat/sparks/open flame/hotsurface/oxidizing gas. No smoking. |
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| Health hazards | If concentration of gas is high enough, may cause asphyxiation. No detectable systemic effects, even at 5% concentration in air. (USCG, 1999)High concentrations may cause asphyxiation. No systemic effects, even at 5% concentration in air. (USCG, 1999)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. |
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| Hazards summary | The Critical Effects for aliphatic hydrocarbon gases are CNS depression and cardiac sensitization. From a toxicologic standpoint, methane and ethane are practically inerthowever, at very high concentrations, they act as a simple asphyxiant and can cause suffocation by displacement of oxygen from breathing atmosphere, below the critical level of 16% oxygen that is required to sustain life. [ACGIH] Simple asphyxiantEvaporating liquid can cause frostbite[ICSC] |
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| DOT ID and guide | 1972 1151971 115 |
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| Reactive group | Hydrocarbons, Aliphatic Saturated |
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| EC classification | Symbol: F+R: 12S: (2)-9-16-33 |
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| UN classification | UN Hazard Class: 2.1 |
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| Reactivity Alerts | Highly Flammable |
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| Fire fighting | Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]:Shut off supplyif 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. |
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| First aid measures | Fresh air, rest. Artificial respiration may be needed. Refer for medical attention.ON FROSTBITE: rinse with plenty of water, do NOT remove clothes. Refer for medical attention .First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention. |
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| Accidental release measures | · 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.· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. |
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| First aid | Remove victim to open air. If he is overcome by gas, apply artificial resuscitation. (USCG, 1999)EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]:General First Aid: |
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| Safe storage | Fireproof. Cool. Ventilation along the floor and ceiling. |
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| Exposure control and personal protection | · Wear positive pressure self-contained breathing apparatus (SCBA). |
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| Fire fighting procedures | Wear self contained breathing apparatus for fire fighting if necessary.Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide. |
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| Storage conditions | Store in a cool, dry, well-ventilated location. Separate from halogens and oxygen. Outside or detached storage is preferred.Protect against physical damage. ... Isolate from oxidizing agents. Prohibit open flame. Inspect for leakage occasionally. |
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| Cleanup methods | Clean up promptly by sweeping or vaccum.Do not let product enter drains.Evacuate danger area! Personal protection: self-contained breathing apparatus. Consult an expert! Ventilation. Remove all ignition sources. NEVER direct water jet on liquid.By forced ventilation, maintain concn of gas below the range of explosive mixture. Remove the tank or cylinder to an open area. Leave to bleed off in the atmosphere. |
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| Nonfire spill response | Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]: |
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| Disposal methods | Offer surplus and non-recyclable solutions to a licensed disposal company. Contact a licensed professional waste disposal service to dispose of this material.SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. 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 qualitypotential migration in soil or watereffects on animal, aquatic, and plant lifeand conformance with environmental and public health regulations. |
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| Spillage disposal | Evacuate danger area! Personal protection: self-contained breathing apparatus. Consult an expert! Ventilation. Remove all ignition sources. NEVER direct water jet on liquid. |
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| Treatment | Asphyxiation should be treated by moving the affected person to an uncontaminated area, then giving artificial respiration and administering oxygen, if necessary. (L173) |
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| Health effects | Methane is an asphyxiant and displaces oxygen in enclosed spaces. At high enough concentrations, oxygen depletion may cause asphyxiation, resulting in generalized hypoxia and possibly death. (L171, L172) |
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| Environmental fate | TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 9(SRC), determined from a log Kow of 1.09(2) and a regression-derived equation(3), indicates that methane is expected to have very high mobility in soil(SRC). Volatilization of methane from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 0.66 atm-cu m/mole(SRC), derived from its vapor pressure, 4.66X10+5 mm Hg(4), and water solubility, 22 mg/L(5). Methane is expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(4). An average utilization of 55% for methane by anaerobic soil microorganisms(6) suggests that biodegradation may be an environmental fate process in soil(SRC).AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 9(SRC), determined from a log Kow of 1.09(2) and a regression-derived equation(3), indicates that methane is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(4) based upon an estimated Henry's Law constant of 0.66 atm-cu m/mole(SRC), derived from its vapor pressure, 4.66X10+5 mm Hg(5), and water solubility, 22 mg/L(6). Using this Henry's Law constant and an estimation method(4), volatilization half-lives for a model river and model lake are 2 hours(SRC). According to a classification scheme(7), an estimated BCF of 2(SRC), from its log Kow(2) and a regression-derived equation(3), suggests the potential for bioconcentration in aquatic organisms is low(SRC). The biodegradation half-life of methane was estimated to range from 70 days to infinity in model anaerobic estuarine ecosystems(8), indicating that biodegradation is not an important environmental fate process in water(SRC).ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), methane, which has a vapor pressure of 4.66X10+5 mm Hg at 25 °C(2), is expected to exist solely as a gas in the ambient atmosphere. Gas-phase methane is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC)the half-life for this reaction in air is estimated to be 4 yrs(3), calculated from its rate constant of 6.85X10-15 cu cm/molecule-sec at 25 °C(4). Methane does not contain chromophores that absorb at wavelengths >290 nm(5) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC). |
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| Adverse effects | Other Poison - Simple Asphyxiant |
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| Exposure routes | The substance can be absorbed into the body by inhalation.Inhalation (L172) |
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| Toxicity summary | Methane is an asphyxiant and displaces oxygen in enclosed spaces. At high enough concentrations, oxygen depletion may cause asphyxiation. Low concentrations of surrounding oxygen results in deficient oxygen to the organs, compounded by increased oxygen exhalation during respiration. This results in generalized hypoxia and possibly death. (L171, A120) |
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| Signs and Symptoms | Suffocation.ON CONTACT WITH LIQUID: FROSTBITE.Symptoms of methane asphyxiation include nausea, vomiting, difficulty breathing, irregular heartbeat, headache, drowsiness, fatigue, dizziness, disorientation, mood swings, tingling sensation, loss of coordination,
suffocation, convulsions, unconsciousness, coma, and possibly death. (L173) |
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| Effluent Concentrations | In exhaust of diesel engine: 17% of emitted hydrocarbonsin exhaust of reciprocating gasoline engine: 24% of emitted hydrocarbonsin exhaust of rotary gasoline engine: 4.9% of emitted hydrocarbonsexpected glc's in USA urgan air: range: 1.6-10 ppmin combustion gas of household central heating on gasoil: 20 ppmin flue gas of municipal incinerator: < 0.4-13.0 ppmin exhaust of gasoline engine: 14-17% of total exhaust hydrocarbons15 fuel survey: 18 vol % of total exhaust hydrocarbonsIn 1990, emissions of methane to the atmosphere were approximately 380 million tons/yrin 1860, 80 million tons/yr of methane were released(1). Methane emissions estimates for 1993 were as follows: gas flaring, 18.0X10+12 g/yrgas supply, 16.9X10+12 g/yrcoal mining 46.3X10+12 g/yrbiomass burning, 38.4X10+12 g/yrlivestock, 112.1X10+12 g/yrrice, 101.4X10+12 g/yrlandfills, 43.9X10+12 g/yr(1). Methane emissions estimates for 1860 were as follows: gas flaring, 0.0X10+12 g/yrgas supply, 0.0X10+12 g/yrcoal mining 2.2X10+12 g/yrbiomass burning, 9.8X10+12 g/yrlivestock, 25.6X10+12 g/yrrice, 40.1X10+12 g/yrlandfills, 1.6X10+12 g/yr(1). Livestock farming is the largest anthropogenic source of methane(1).Methane was detected in the flue gas of an incineration plant located in the town of Babylon, NY during three different tests at concentrations ranging from less than 0.4 to 13.0 ppm(1). Methane was found in combustion gas of light fuel oil at concentrations ranging from 0.32 to 26.80 mL/L and it was detected in the exhaust gas of light fuel oil at a concentration of 0.11 mL/L(2). Automotive exhaust emissions have been found to contain methane(6,7). It was found to be present in effluents from coal combustion(3). Methane was detected in ten samples of emissions from jet engines at concentrations ranging from 0.05 to 48.0 ppm(4). Wood smoke has been found to contain methane in the gas-phase at final concentrations of 4,500 and 3,920 ppb(5). Methane was detected in the ambient air of five California landfills at concentrations ranging from 16,600 to 587,000 ppm(8). The rate of methane from fireplace combustion of wood was 4,120 mg/kg wood burned(9). The concentration of methane measured in the Caldecott Tunnel located in San Francisco Bay, CA was approx 413 mg/L during a period when low oxygenated fuel was used(10). When high oxygenated fuel was used, the concentration of methane in tunnel air was about 459 mg/L(10).Direct measurement of methane (CH4) flux from wetland ecosystems of south Florida demonstrates that freshwater wet prairies and inundated sawgrass marsh are the dominant sources of atmospheric CH4 in the region(1). Fluctuations in soil moisture are an important environmental factor controlling both seasonal and interannual fluctuations in CH4 emissions from undisturbed wetlands(1). Land use estimates for 1900 and 1973 were used to calculate regional CH4 flux(1). Human settlement in south Florida has modified wetland sources of CH4, reducing the natural prairies and marsh sources by 37%(1). During the same period, impoundments and disturbed wetlands were created which produce CH4 at rates approximately 50% higher than the natural wetlands they replaced(1). The mean standard error, in mg methane/sq m/day, was 61 for wet prairies and sawgrass marsh, 59 for wetland forests, 4 for saltwater mangroves, and 74 for impoundments and disturbed wetlands(1). |
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| Soil Adsorption/Mobility | The Koc of methane is estimated as 9(SRC), using a log Kow of 1.09(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that methane is expected to have very high mobility in soil. Methane's vapor pressure of 4.7X10+5 mm Hg(4) suggests that this compound will permeate through soil(SRC). |
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| Natural Pollution Sources | Methane may be released to the environment as emissions from microbes, animal waste and volcanoes(1,2). Methane is the principal constituent of natural gas(1,3)natural gas from America is approximately 85% methane(4). Emissions of geothermal steam may release methane to the environment(1,5). Methane is a constituent of petroleum gases(6). An important source of methane is the rumen of domestic animals, especially of cattle(7). Methane may be released to the environment through emissions during the growing of rice(7).Methane is found as hydrates (i.e., methane hydrate) in immense amounts both in Arctic regions and in marine sediments(1). Methane hydrate is stable in ocean floor sediments at water depths greater than 300 meters, and where it occurs, it is known to cement loose sediments in a surface layer several hundred meters thick(1). The worldwide amounts of carbon bound as gas hydrates (e.g., methane hydrate) is conservatively estimated to total twice the amount of carbon found in all known fossil fuels on Earth(1). The earth's atmosphere contains 0.00022% methane by volume(2).Potential rates of methane generation and carbon dioxide generation were measured on 11 dates in 1986 in peat from six plant communities typical of moss dominated peatlands in the Appalachian Mountains(1). Annual methane generation ranged from 2.7 to 17.5 M/sq m, and annual carbon dioxide production ranged from 30.6 to 79.0 M/sq m(1). The wide range in methane generation values among the communities found within a single peatland indicates that obtaining one generation value for a peatland may not be appropriate(1). Low temperature constrained the potential for methane generation in winter, while the chemical quality of the peat substrate appears to control methane generation in the summer(1). Methane oxidation was measured throughout the peat profile to a depth of 30 cm(1). Values for methane oxidation ranged from 0.08 to 18.7 uM/hr among the six plant communities(1). Aerobic methane oxidizing bacteria probably mediated most of the activity(1). On a daily basis during the summer, between 11 and 100% of the methane generated is susceptible to oxidation within the peat column(1). Pools of dissolved methane and dissolved carbon dioxide in pore waters were <0.2 and <1.0 M/sq m, respectively, indicating that methane does not accumulate in the pore waters. Peatlands have been considered as an important source of biologically produced methane(1). Despite the high rates of methane generation, the high rates of methane oxidation dampen the potential emission of methane to the atmosphere(1).C(14) content of atmospheric methane prior to nuclear adn thermal nuclear bomb-testing contamination suggests that greater than 80% of atmospheric methane is from decay of recent organic matter. /14(C)-Methane/ |
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| Atmospheric Concentrations | A factor of 2.5 increase in the global abundance of atmospheric methane (CH(4)) since 1750 contributes 0.5 Wm(-2) to total direct radiative forcing by long-lived greenhouse gases (2.77 Wm(-2) in 2009), while its role in atmospheric chemistry adds another approximately 0.2 Wm(-2) of indirect forcing. Since CH(4) has a relatively short lifetime and it is very close to a steady state, reductions in its emissions would quickly benefit climate. Sensible emission mitigation strategies require quantitative understanding of CH(4)'s budget of emissions and sinks. Atmospheric observations of CH(4) abundance and its rate of increase, combined with an estimate of the CH(4) lifetime, constrain total global CH(4) emissions to between 500 and 600 Tg CH(4) yr(-1). While total global emissions are constrained reasonably well, estimates of emissions by source sector vary by up to a factor of 2. Current observation networks are suitable to constrain emissions at large scales (e.g. global) but not at the regional to national scales necessary to verify emission reductions under emissions trading schemes. Improved constraints on the global CH(4) budget and its break down of emissions by source sector and country will come from an enhanced observation network for CH(4) abundance and its isotopic composition (delta(13)C, deltaD(D=(2)H) and delta(14)C). Isotopic measurements are a valuable tool in distinguishing among various sources that contribute emissions to an air parcel, once fractionation by loss processes is accounted for. Isotopic measurements are especially useful at regional scales where signals are larger. Reducing emissions from many anthropogenic source sectors is cost-effective, but these gains may be cancelled, in part, by increasing emissions related to economic development in many parts of the world. An observation network that can quantitatively assess these changing emissions, both positive and negative, is required, especially in the context of emissions trading schemes.Methane is an important greenhouse gas, and its atmospheric concentration has nearly tripled since pre-industrial times. The growth rate of atmospheric methane is determined by the balance between surface emissions and photochemical destruction by the hydroxyl radical, the major atmospheric oxidant. Remarkably, this growth rate has decreased markedly since the early 1990s, and the level of methane has remained relatively constant since 1999, leading to a downward revision of its projected influence on global temperatures. Large fluctuations in the growth rate of atmospheric methane are also observed from one year to the next, but their causes remain uncertain. Here we quantify the processes that controlled variations in methane emissions between 1984 and 2003 using an inversion model of atmospheric transport and chemistry. Our results indicate that wetland emissions dominated the inter-annual variability of methane sources, whereas fire emissions played a smaller role, except during the 1997-1998 El Nino event. These top-down estimates of changes in wetland and fire emissions are in good agreement with independent estimates based on remote sensing information and biogeochemical models. On longer timescales, our results show that the decrease in atmospheric methane growth during the 1990s was caused by a decline in anthropogenic emissions. Since 1999, however, they indicate that anthropogenic emissions of methane have risen again. The effect of this increase on the growth rate of atmospheric methane has been masked by a coincident decrease in wetland emissions, but atmospheric methane levels may increase in the near future if wetland emissions return to their mean 1990s levels.URBAN/SUBURBAN: The concentration of methane measured at Exhibition Road, London, UK ranged from 1.34-2.45 ppm (average, 1.59 ppm) between the period of January 1991 to July 1992(1). Methane has been detected in five air samples collected in Houston, TX on April 2, 1974 at concentrations ranging from 1.91 to 2.31 ppm(2). Methane detected of Riverside, CA in smoggy air at 2.02 ppm(3).URBAN/SUBURBAN: Methane emission in the Mexico City Metropolitan Area, 2000(1).For more Atmospheric Concentrations (Complete) data for METHANE (7 total), please visit the HSDB record page. |
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| Human Toxicity Excerpts | /HUMAN EXPOSURE STUDIES/ ...May cause frostbite /like effects/ on skin contact. /Liquified methane//HUMAN EXPOSURE STUDIES/ ... Methane... acts as a simple asphyxiant when inhaled. /Its/ presence displaces air, which lowers the partial pressure of oxygen and causes hypoxia./CASE REPORTS/ It has been known that methane gas intoxication causes loss of consciousness or asphyxia. There is, however, a paucity of information about acute pulmonary toxicity from methane gas inhalation. A 21-year-old man was presented with respiratory distress after an accidental exposure to methane gas for one minute. He came in with a drowsy mentality and hypoxemia. Mechanical ventilation was applied immediately. The patient's symptoms and chest radiographic findings were consistent with acute pneumonitis. He recovered spontaneously and was discharged after 5 days without other specific treatment. His pulmonary function test, 4 days after methane gas exposure, revealed a restrictive ventilatory defect. In conclusion, acute pulmonary injury can occur with a restrictive ventilator defect after a short exposure to methane gas. The lung injury was spontaneously resolved without any significant sequela./OTHER TOXICITY INFORMATION/ The impact of major gaseous and particulate pollutants emitted by the wildfire of October 2003 on ambient air quality and health of San Diego residents before, during, and after the fire are analyzed using data available from the San Diego County Air Pollution Control District and California Air Resources Board. It was found that fine particulate matter (PM) levels exceeded the federal daily 24-hr average standard during the fire. There was a slight increase in some of the gaseous pollutants, such as carbon monoxide, which exceeded federal standards. Ozone (O3) precursors, such as total hydrocarbons and methane gases, experienced elevated concentration during the fire. Fortunately, the absence of sunlight because of the cloud of thick smoke that covered most of the county during the fire appears to have prevented the photochemical conversion of the precursor gases to harmful concentrations of O3. Statistical analysis of the compiled medical surveillance data has been used to establish correlations between pollutant levels in the region and the resultant health problems experienced by the county citizens. The study shows that the increased PM concentration above the federal standard resulted in a significant increase in hospital emergency room visits for asthma, respiratory problems, eye irritation, and smoke inhalation.../OTHER TOXICITY INFORMATION/ A simple asphyxiant. |
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| DHS Chemicals of Interest (COI) | Methane110000Flammable chemical that can be released at a facility. |
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| Signal word | Danger |
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| GHS pictogram | GHS02,GHS04 |
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| GHS hazard statements | H220-H280 |
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| GHS precautionary statements | P210-P377-P381-P410+P403 |
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