| 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, P377, P381, P403, and P410+P403 (click each P-code to see the statement) |
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| Regulatory information | Chemical: EthyneEthyne is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of Ethyne 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: 18-05-2022 https://echa.europa.eu/registration-dossier/-/registered-dossier/15518Ethyne (acetylene): HSNO Approval: HSR000987 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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| DOT label | Flammable Gas |
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| Fire hazards | Behavior in Fire: May explode in fire (USCG, 1999)· EXTREMELY FLAMMABLE.Extremely flammable. Gas/air mixtures are explosive. |
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| Fire potential | Very dangerous fire hazard when exposed to heat or flame ...Generation of acetylene, compression...& storage of cylinders...all entail fire...hazards...Flammable gas ... Low ignition energy ... /Acetylene, dissolved/... /Acetylene/ decomposes on heating and increasing pressure, causing fire and explosion hazard.Extremely flammable. |
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| Health hazards | Headache, dizziness and loss of consciousness may occur. Death from "smothering" may occur if oxygen content of the air is severely reduced by dilution with acetylene. (USCG, 1999)· Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas. |
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| Hazards summary | Acetylene is an explosive hazard and simple asphyxiant. [LaDou, p. 558] Possible frostbite from contact with liquid[NIOSH] Acetylene is in the list of Some volatile substances which may be abused by inhalation published on the web site of the U.N. International Drug Control Programme, indicating its potential to cause narcosis in workers. [Reference #1] |
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| DOT ID and guide | 1001 116 |
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| Reactive group | Alkynes, with Acetylenic Hydrogen |
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| EC classification | Symbol: F+R: 5-6-12S: (2)-9-16-33 |
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| UN classification | UN Hazard Class: 2.1 |
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| Special Reports | European Chemicals BureauIUCLID Dataset, Acetylene (74-86-2) (2000 CD-ROM edition). Information on usage patterns, toxicity, and environmental effects supplied by industry to the European Union.[Available from, as of September 11, 2006: http://esis.jrc.ec.europa.eu/]EPA/Office of Pollution Prevention and ToxicsHigh Production Volume (HPV) Challenge Program's Robust Summaries and Test Plans for Acetylene (December 2003). Evaluates information on usage patterns, toxicity, and environmental effects supplied by industry to the U.S. EPA HPV Challenge Program.[Available from, as of April 6, 2014: http://www.epa.gov/chemrtk/pubs/summaries/acetylen/c15005.pdf] |
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| Reactivity Alerts | Highly Flammable |
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| Fire fighting | Excerpt from ERG Guide 116 [Gases - Flammable (Unstable)]:Shut off supplyif not possible and no risk to surroundings, let the fire burn itself out. In other cases extinguish with powder, carbon dioxide. In case of fire: keep cylinder cool by spraying with water. |
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| First aid measures | Fresh air, rest. Artificial respiration may be needed. 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 | Excerpt from NIOSH Pocket Guide for Acetylene:General First Aid:(General first aid procedures) |
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| Safe storage | Fireproof. See Chemical Dangers. Cool. |
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| Firefighting Hazards | On loss of containment this gas can cause suffocation by lowering the oxygen content of the air in confined areas.Simple asphyxiant. /Acetylene, dissolved/ |
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| Exposure control and personal protection | · Wear positive pressure self-contained breathing apparatus (SCBA). |
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| Fire fighting procedures | Stop flow of gas before extinguishing fire. Use water spray to keep fire-exposed containers cool. Approach fire from upwind to avoid hazardous vapors and toxic decomposition products. Fight fire from protected location or maximum possible distance. Use water spray, dry chemical, form, or carbon dioxide. /Acetylene, dissolved/Stop flow of gas. ... Carbon dioxide, dry chemical and water spray are not generally recommended because the discharged gas or volatile liquid may create a more serious explosion hazard.If material on fire or involved in fire: Do not extinguish fire unless flow can be stopped. Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. /Acetylene, dissolvedAcetylene, solvent free/Evacuation: If fire becomes uncontrollable or container is exposed to direct flame - consider evacuation of one-third (1/3) mile radius. ... /Acetylene, dissolvedFor more Fire Fighting Procedures (Complete) data for ACETYLENE (9 total), please visit the HSDB record page. |
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| Storage conditions | Keep container in a cool, well-ventilated area. Keep container tightly closed and sealed until ready for use. Avoid all possible sources of ignition (spark or flame). Segregate from oxidizing materials. Cylinders should be stored upright, with valve protection cap in place, and firmly secured to prevent falling or being knocked over. Cylinder temperatures should not exceed 52 degC (125 degF).Acetylene can be stored as a gas or in solution. Gaseous acetylene becomes highly explosive when compressed or heated and consequently it is stored under low pressure in large tanks or gasholders.Outside or detached storage is preferred. Isolate from oxidizing gases, especially chlorine. Store in a cool , dry, well-ventilated location. Store cylinders upright. /Acetylene, dissolved/Acetylene in process may be stored in atmospheric gas holders. May be stored in conventional compressed gas cylinders. Content of lines carrying acetylene must not exceed 63% copper (Cu). Storage of liquid acetylene should be avoided. |
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| Cleanup methods | Evacuate danger area! Consult an expert! Ventilation. Remove all ignition sources. (Extra personal protection: self-contained breathing apparatus).Eliminate all ignition sources. Stop or control the leak, if this can be done without undue risk. Use water spray to cool and disperse vapors and protect personnel. /Acetylene, dissolved/ |
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| Nonfire spill response | Excerpt from ERG Guide 116 [Gases - Flammable (Unstable)]: |
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| Disposal methods | SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity 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 and plant lifeand conformance with environmental and public health regulations.SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.Gas Leakage. By forced ventilation, maintain concentration of gas below the range of explosive mixture. Remove the tank or cylinder to an open area. Leave to bleed off in the atmosphere. Disposal. Fit a pipe line into a furnace or into a pit and burn with care.Product removed from the cylinder must be disposed of in accordance with appropriate Federal, State, local regulation. ... Do not dispose of locally. |
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| Interactions | /Acetylene/ produces varying degrees of temporary and reversible /CNS depression/ when administered with oxygen in concentrations of 100,000 ppm ...In humans, the author reported a stimulation of respiration by acetylene-oxygen mixtures (700000 - 800000 ppm). However, all but two of the seven subjects studied had been premedicated with a morphine-containing preparation which affects respiration.The authors observed a rise in the blood pressure of cats administered acetylene-oxygen mixtures containing up to 800000 ppm. No increase was observed if the anesthetic was administered slowly and carefully.Respiration in cats and rabbits was decreased when acetylene-oxygen mixtures were administered.For more Interactions (Complete) data for ACETYLENE (7 total), please visit the HSDB record page. |
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| Target organs | central nervous system, respiratory system |
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| Ecotoxicity values | LC50Species: Salmo fario (river trout)Concentration: 200 mg/L for 33 hr /Conditions of bioassay not specified/ |
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| Environmental fate | TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 2(SRC), determined from a log Kow of 0.37(2) and a regression-derived equation(3), indicates that acetylene is expected to have very high mobility in soil(SRC). Volatilization of acetylene from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 2.2X10-2 atm-cu m/mole(SRC), derived from its vapor pressure, 3.65X10+4 mm Hg(4), and water solubility, 1,200 mg/L(5). Acetylene is expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(4). A 0% theoretical BOD in 28 days using an activated sludge inoculum in the Japanese MITI test(6) suggests that biodegradation is not expected to be an important environmental fate process in soil(SRC).AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 2(SRC), determined from a log Kow of 0.37(2) and a regression-derived equation(3), indicates that acetylene 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 2.2X10-2 atm-cu m/mole(SRC), derived from its vapor pressure, 3.65X10+4 mm Hg(5), and water solubility, 1,200 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 1.5 hrs and 2 days, respectively(SRC). According to a classification scheme(7), an estimated BCF of 3(SRC), from its log Kow(2) and a regression-derived equation(3), suggests the potential for bioconcentration in aquatic organisms is low(SRC). A 0% theoretical BOD in 28 days using an activated sludge inoculum in the Japanese MITI test(8) suggests that biodegradation is not expected to be 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), acetylene, which has a vapor pressure of 3.65X10+4 mm Hg at 25 °C(2), is expected to exist solely as a gas in the ambient atmosphere. Gas-phase acetylene 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 20 days(SRC), calculated from its rate constant of 8.15X10-13 cu cm/molecule-sec at 25 °C(3). Acetylene has a calculated global lifetimes ranging from 14 days(4) to 32 days(5) in the atmosphere. Acetylene does not contain chromophores that absorb at wavelengths >290 nm(6) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC). |
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| Adverse effects | Neurotoxin - Acute solvent syndrome |
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| Exposure routes | The substance can be absorbed into the body by inhalation.inhalation, skin and/or eye contact (liquid) |
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| Signs and Symptoms | Dizziness. Lethargy. Headache. Suffocation.headache, dizzinessasphyxialiquid: frostbite |
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| Effluent Concentrations | Acetylene was found in whole gas octane levels 87, 89 and 92 at 0.0022, 0.0032 and 0.0037 ppbC%, respectively(1). Acetylene has been detected 12%, 2.9% and 50% of total hydrocarbon concentration in emissions from vehicle exhaust, petroleum exhaust and petrochemical plants, respectively(2). Acetylene has been estimated to be about 12.69% of total organic gases released in exhaust from small engines(3). Acetylene was released from catalyst and non-catalyst equipped gasoline powered motor vehicle tailpipes at concentrations of 12,800 and 865,00 ug/km, respectively(4). Hydrocarbon speciation of acetylene in exhaust emissions typically are 0.0376, 0.0, and 0.0% of engine exhaust under cold start, hot stab, and hot start exhaust emissions, respectively(5). Acetylene in the air at bus garages and from motorcycle emissions in Egypt comprised of 1.3-1.7 and 3.38% by weight, respectively, of the non-methane organic contaminants in these areas(6).Acetylene was released from the pyrolysis and combustion of scrap tire at the concentrations ranging from 0.73-1.07 and 0.002-0.54 mg/100 mg of scrap tire(1).Acetylene comprised of 4.11, 0.34, 0.77 and 1.24% of nonmethane organic carbon emissions monitored in restaurants, tortilla, rotisserie and fried food in Mexico(1). |
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| Soil Adsorption/Mobility | The Koc of acetylene is estimated as 2(SRC), using a log Kow of 0.37(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that acetylene is expected to have very high mobility in soil. Less than 1 ppm of gas acetylene was absorbed to dry soil and a maximum of 90 ppm of acetylene was absorbed to moist soil samples taken from 6 soil samples from Oregon, Iowa and Saskatchewan, Canada(4). |
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| Natural Pollution Sources | Acetylene was present in fine particle emissions from burning of Lobolly pine, Western Hemlock, Ponderosa pine (Pinaceae), Aceraceae/Fagaceae, Palmae/Pinaceae, and Poaceae/Pinaceae trees(1). Acetylene is released from burning wood in fireplaces and stoves(2). |
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| Atmospheric Concentrations | URBAN/SUBURBAN: In Azuza, CA ambient acetylene value of 100 ug/cu m was measured during September 8-9 1993(1). Acetylene was found in 13/13 samples around the US during 1996 at concentrations greater than 1 ppbv(2). Acetylene was detected in the air of Taipei, Taiwan with a median concentration of 11,600 parts per trillion by volume(3). Industrial and downtown air from Edmonton, Canada during 1991-1993 had median concentrations of 2.19 and 5.89 ug/cu m, respectively(4). Acetylene was detected with a mean concentration of 40.2 mg/cu m in urban air from Porto Alegre, Brazil, March 1996-April 16, 1997(5). An observed ambient acetylene concentration of 16 ug/cu m was reported September 8-9,1993 in California south coast air(6). Acetylene was detected in 97% of the air samples taken from Washington, DC from March 1990 to March 1991 with a mean concentration of 16.1 ppbv(7). Acetylene was detected in background, residential and street site locations in Berlin, Germany from June to August 1996 in concentrations 0.47, 1.95 and 4.79 ug/cu m, respectively(8). Acetylene is labeled as one of the most prevalent non-methane organic compounds identified in urban air(9). The compound was detected at an average concentration of 4.01 ppbv in air samples from Beijing, China, sampled from June-September, 2008(10).URBAN/SUBURBAN: ... expected ground level concentrations in USA urban air: 15 to 250 ppbRURAL/REMOTE: Acetylene was present in air samples taken at Whiteface Mountain, Wilmington, NY, a rural mountain site in northeastern United States. Samples were collected during 12-16 July, 1994. Average concentrations were 4.2 and 3.5% of total carbon detected for nighttime and daytime, respectively. The remote site is affected by west-northesterly winds which advect photochemically-aged air masses that have been subject to anthropogenic emissions(1).SOURCE DOMINATED: Acetylene in the air near roadways, lead smelter plants, and cast iron factories in Egypt comprised of 5.48, 0.12 and 0.40% by weight of the non-methane organic contaminants, respectively(1). |
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| Human Toxicity Excerpts | /HUMAN EXPOSURE STUDIES/ In humans, acetylene is not acutely toxic below its lower explosive limit of 2.5% (25,000 ppm). Inhalation of 10% acetylene (100,000 ppm) for 1 hour does not cause acute toxicity. Inhalation of 33% or 35% has caused unconsciousness within 7 and 5 minutes, respectively .../HUMAN EXPOSURE STUDIES/ Humans exposed to 35% acetylene were unconscious after 5 min. Commencing intoxication was observed after 25 sec, marked intoxication after 1 min./SIGNS AND SYMPTOMS/ A simple asphyxiant. High concentrations cause /CNS depression/. 20% concentration may cause dyspnea, headache40% or more concentration may cause collapse./SIGNS AND SYMPTOMS/ Acute local: 0. Chronic local: 0. Chronic systemic: inhalation 1. 0= none: no harm under any conditions or harmful only under unusual conditions or overwhelming dosage. 1= slight: causes readily reversible changes which disappear after end of exposure. Acute systemic: inhalation 2. 2= moderate: may involve both irreversible and reversible changes not severe enough to cause death or permanent injury.For more Human Toxicity Excerpts (Complete) data for ACETYLENE (22 total), please visit the HSDB record page. |
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| Atmospheric standards | This action promulgates standards of performance for equipment leaks of Volatile Organic Compounds (VOC) in the Synthetic Organic Chemical Manufacturing Industry (SOCMI). The intended effect of these standards is to require all newly constructed, modified, and reconstructed SOCMI process units to use the best demonstrated system of continuous emission reduction for equipment leaks of VOC, considering costs, non air quality health and environmental impact and energy requirements. Acetylene is produced, as an intermediate or a final product, by process units covered under this subpart. |
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| DHS Chemicals of Interest (COI) | Acetylene110000Flammable chemical that can be released at a facility. |
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