acetylene

H220: 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]

H280 (68.6%): Contains gas under pressure; may explode if heated [Warning Gases under pressure]

P203, P210, P222, P280, P377, P381, P403, and P410+P403 (click each P-code to see the statement)

Aggregated GHS information provided per 455 reports by companies from 15 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

H280: Contains gas under pressure; may explode if heated [Warning Gases under pressure]

H336: May cause drowsiness or dizziness [Warning Specific target organ toxicity, single exposure; Narcotic effects]

P203, P210, P222, P261, P271, P280, P304+P340, P319, P377, P381, P403, P403+P233, P405, P410+P403, and P501 (click each P-code to see the statement)

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.

Excerpt from NIOSH Pocket Guide for Acetylene:

Eye: FROSTBITE - If eye tissue is frozen, seek medical attention immediately; if tissue is not frozen, immediately and thoroughly flush the eyes with large amounts of water for at least 15 minutes, occasionally lifting the lower and upper eyelids. If irritation, pain, swelling, lacrimation, or photophobia persist, get medical attention as soon as possible.

Skin: FROSTBITE - If frostbite has occurred, seek medical attention immediately; do NOT rub the affected areas or flush them with water. In order to prevent further tissue damage, do NOT attempt to remove frozen clothing from frostbitten areas. If frostbite has NOT occurred, immediately and thoroughly wash contaminated skin with soap and water.

Breathing: FRESH AIR - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. Other measures are usually unnecessary. (NIOSH, 2024)

General First Aid:

· Call 911 or emergency medical service.

· Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.

· Move victim to fresh air if it can be done safely.

· Administer oxygen if breathing is difficult.

· If victim is not breathing:

-- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.

-- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).

-- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.

· Remove and isolate contaminated clothing and shoes.

· For minor skin contact, avoid spreading material on unaffected skin.

· In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.

· For severe burns, immediate medical attention is required.

· Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed.

· Keep victim calm and warm.

· Keep victim under observation.

· For further assistance, contact your local Poison Control Center.

· Note: Basic Life Support (BLS) and Advanced Life Support (ALS) should be done by trained professionals.

Specific First Aid:

· In case of contact with liquefied gas, only medical personnel should attempt thawing frosted parts.

· In case of burns, immediately cool affected skin for as long as possible with cold water. Do not remove clothing if adhering to skin.

In Canada, an Emergency Response Assistance Plan (ERAP) may be required for this product. Please consult the shipping paper and/or the "ERAP" section.

(General first aid procedures)

Eye: Frostbite - If eye tissue is frozen, seek medical attention immediately; if tissue is not frozen, immediately and thoroughly flush the eyes with large amounts of water for at least 15 minutes, occasionally lifting the lower and upper eyelids. If irritation, pain, swelling, lacrimation, or photophobia persist, get medical attention as soon as possible.

Skin: Frostbite - Compressed gases may create low temperatures when they expand rapidly. Leaks and uses that allow rapid expansion may cause a frostbite hazard. Wear appropriate personal protective clothing to prevent the skin from becoming frozen.

Breathing: Fresh air

Excerpt from ERG Guide 116 [Gases - Flammable (Unstable)]:

DO NOT EXTINGUISH A LEAKING GAS FIRE UNLESS LEAK CAN BE STOPPED.

SMALL FIRE: Dry chemical or CO2.

LARGE FIRE: Water spray or fog. If it can be done safely, move undamaged containers away from the area around the fire.

FIRE INVOLVING TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Do not direct water at source of leak or safety devices; icing may occur. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2024)

Shut off supply; if 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.

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, dissolved; Acetylene, solvent free/

Evacuation: If fire becomes uncontrollable or container is exposed to direct flame - consider evacuation of one-third (1/3) mile radius. ... /Acetylene, dissolved; Acetylene, solvent free/

For more Fire Fighting Procedures (Complete) data for ACETYLENE (9 total), please visit the HSDB record page.

On loss of containment this gas can cause suffocation by lowering the oxygen content of the air in confined areas.

Simple asphyxiant. /Acetylene, dissolved/

· 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.

· Keep unauthorized personnel away.

· Stay upwind, uphill and/or upstream.

· Many gases are heavier than air and will spread along the ground and collect in low or confined areas (sewers, basements, tanks, etc.).

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

· All equipment used when handling the product must be grounded.

· Stop leak if you can do it without risk.

· Do not touch or walk through spilled material.

· Do not direct water at spill or source of leak.

· Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material.

· If possible, turn leaking containers so that gas escapes rather than liquid.

· Prevent entry into waterways, sewers, basements or confined areas.

· Isolate area until gas has dispersed.

Excerpt from ERG Guide 116 [Gases - Flammable (Unstable)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 100 meters (330 feet) in all directions.

LARGE SPILL: Consider initial downwind evacuation for at least 800 meters (1/2 mile).

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 1600 meters (1 mile) in all directions; also, consider initial evacuation for 1600 meters (1 mile) in all directions. (ERG, 2024)

Immediate precautionary measure

· Isolate spill or leak area for at least 100 meters (330 feet) in all directions.

Large Spill

· Consider initial downwind evacuation for at least 800 meters (1/2 mile).

· If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 1600 meters (1 mile) in all directions; also, consider initial evacuation for 1600 meters (1 mile) in all directions.

Remove all ignition sources. Evacuate danger area! Consult an expert! Personal protection: self-contained breathing apparatus. Ventilation.

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/

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 quality; potential migration in soil or water; effects on animal and plant life; and 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.

Any leakage of acetylene will constitute a fire or explosion hazard and must be controlled immediately. Due to the characteristic odor, leaking gas is relatively easy to detect; the precise location of the leak should be determined by wiping soapy water over the suspected area--naked lights should never be used.

Areas should be kept dry, well ventilated and shielded from direct sunlight; ventilation openings should never be blocked in cold weather. Smoking, naked lights and other sources of ignition must be strictly forbidden, electrical equipment and lighting and heating facilities should be explosion proof and any hand tools employed should be of the non-sparking type. Containers, pipes, valves or fittings made of copper or copper alloys (brass, bronze) should not be used. Cylinders of dissolved acetylene should be handled carefully to prevent shocks. If a gas cylinder shows signs of internal heating the valve must be closed if possible and the cylinder liberally sprinkled using a fire extinguisher. Before any repairs or adjustments are made to containers or piping which have held acetylene, they must be well purged (with nitrogen for example) and, if necessary, completely filled with water. Dissolved acetylene should not be withdrawn from the cylinder at an hourly rate greater than a value depending on the type of the cylinder and in particular its diameter. A too fast withdrawal may carry over solvent, leaving gaseous acetylene at high pressure or may cause static electricity sparks. In installations for the manufacture or use of acetylene, safety devices must be provided to reduce pressure and flashbacks and to prevent the formation of explosive mixt. Personnel should be informed about the safety rules to be followed and not depart in any way from instructions.

Work clothing that becomes wet should be immediately removed due to its flammability hazard (i.e., for liquids with a flash point <100 °F).

Personnel protection: Avoid breathing vapors. Keep upwind. ... Do not handle broken packages unless wearing appropriate personal protective equipment. Approach fire with caution. /Acetylene, dissolved; Acetylene, solvent free/

For more Preventive Measures (Complete) data for ACETYLENE (20 total), please visit the HSDB record page.

Excerpt from ERG Guide 116 [Gases - Flammable (Unstable)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Stop leak if you can do it without risk. Do not touch or walk through spilled material. Do not direct water at spill or source of leak. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. If possible, turn leaking containers so that gas escapes rather than liquid. Prevent entry into waterways, sewers, basements or confined areas. Isolate area until gas has dispersed. (ERG, 2024)

Fireproof. See Chemical Dangers. Cool.

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.

· Wear positive pressure self-contained breathing apparatus (SCBA).

· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

65000 [ppm]

230000 [ppm]

400000 [ppm]

C 2500 ppm (2662 mg/m3)

See: IDLH INDEX

· DO NOT EXTINGUISH A LEAKING GAS FIRE UNLESS LEAK CAN BE STOPPED.

Small Fire

· Dry chemical or CO2.

Large Fire

· Water spray or fog.

· If it can be done safely, move undamaged containers away from the area around the fire.

Fire Involving Tanks

· Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles.

· Cool containers with flooding quantities of water until well after fire is out.

· Do not direct water at source of leak or safety devices; icing may occur.

· Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank.

· ALWAYS stay away from tanks in direct contact with flames.

· For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn.

On loss of containment this substance can cause suffocation by lowering the oxygen content of the air in confined areas.

Asphyxiation.

Excerpt from NIOSH Pocket Guide for Acetylene:

Skin: FROSTBITE - Compressed gases may create low temperatures when they expand rapidly. Leaks and uses that allow rapid expansion may cause a frostbite hazard. Wear appropriate personal protective clothing to prevent the skin from becoming frozen.

Eyes: FROSTBITE - Wear appropriate eye protection to prevent eye contact with the liquid that could result in burns or tissue damage from frostbite.

Wash skin: No recommendation is made specifying the need for washing the substance from the skin (either immediately or at the end of the work shift).

Remove: WHEN WET (FLAMMABLE) - Work clothing that becomes wet should be immediately removed due to its flammability hazard (i.e., for liquids with a flash point <100 °F).

Change: No recommendation is made specifying the need for the worker to change clothing after the workshift.

Provide: FROSTBITE WASH - Quick drench facilities and/or eyewash fountains should be provided within the immediate work area for emergency use where there is any possibility of exposure to liquids that are extremely cold or rapidly evaporating. (NIOSH, 2024)

Where conditions ... are such that ... impurities may constitute health hazard, composition of acetylene should be determined. Respiratory protective equipment is not normally required ... /but/ self-contained type should be available for emergency and rescue use.

Compressed gases may create low temperatures when they expand rapidly. Leaks and uses that allow rapid expansion may cause a frostbite hazard. Wear appropriate personal protective clothing to prevent the skin from becoming frozen.

Wear appropriate eye protection to prevent eye contact with the liquid that could result in burns or tissue damage from frostbite.

Quick drench facilities and/or eyewash fountains should be provided within the immediate work area for emergency use where there is any possibility of exposure to liquids that are extremely cold or rapidly evaporating.

For more Personal Protective Equipment (PPE) (Complete) data for ACETYLENE (9 total), please visit the HSDB record page.

Important additional information about respirator selection

NO open flames, NO sparks and NO smoking. Closed system, ventilation, explosion-proof electrical equipment and lighting. Prevent build-up of electrostatic charges (e.g., by grounding). Use non-sparking handtools. Flame arrester to prevent flash-back from burner to cylinder.

Use ventilation, local exhaust or breathing protection.

Do not eat, drink, or smoke during work.

Acetylene appears as a colorless gas with a faint garlic-like odor. Easily ignited and burns with a sooty flame. Gas is lighter than air. Flame may flash back to the source of a leak very easily. Under prolonged exposure to fire or heat the containers may rupture violently and rocket.

Liquid; Gas Vapor; CBI

Colorless gas with a faint, ethereal odor. [Note: Commercial grade has a garlic-like odor. Shipped under pressure dissolved in acetone.] [NIOSH] Vapor density = 0.91 (lighter than air); [HSDB]

COLOURLESS GAS DISSOLVED IN ACETONE UNDER PRESSURE.

Colorless gas with a faint, ethereal odor. [Note: Commercial grade has a garlic-like odor. Shipped under pressure dissolved in acetone.]

Colorless gas ... [Note: Shipped under pressure dissolved in acetone]

Not unpleasant odor unless impure (due to phosphine)

FAINT ODOR OF ETHER

... Faint, ethereal odor [Note: Commercial grade has a garlic-like odor ...]

-119 °F at 760 mmHg (USCG, 1999)

-84.7 °C (sublimation point)

BP: -84 °C sublimes

-84 °C @760 [mm Hg]

Sublimes

-119 °F (Sublimes) (NIOSH, 2024)

-80.7 °C (triple point)

-80.7 °C

-119 °F (Sublimes)

Closed cup: -18.15 °C (-0.7 °F).

Flammable gas

NA (Gas)

2 % (NIOSH, 2024)

In water, 1200 mg/L at 25 °C

Soluble in water and many organic materials

Slightly soluble in ethanol, carbon disulfide; soluble in acetone, benzene, chloroform

One volume dissolves in 6 volumes of glacial acetic acid or alcohol. Soluble in ether, benzene. Acetone dissolves 25 volume at 15 °C, 760 mm Hg; acetone dissolves 300 vol at 12 atm

Moderately soluble in ethanol and acetic acid; very soluble in Me2CO; almost miscible in ether

Solubility in water, g/100ml at 20 °C: 0.12

0.613 at -112 °F (USCG, 1999) - Less dense than water; will float

0.377 g/cu cm (pressure >1 atm)

1 L weighs 1.165 g at 0 °C and 760 mm Hg; density of gas: 0.90 (Air = 1); below 37 °C (critical temp) it liquifies at 68 atm; at 0 °C it liquifies at 21.5 atm

0.909 @ 0°C

0.91(relative gas density)

0.91 (NIOSH, 2024) - Lighter than air; will rise (Relative to Air)

0.91 (Air = 1)

Relative vapor density (air = 1): 0.907

44.2 atm (NIOSH, 2024)

Vapor pressure = 40 atm at 16.8 °C

Vapor pressure, kPa at 20 °C: 4460

30780 [mm Hg] @20 °C

Highly flammable. Slightly soluble in water.

Alkynes, with Acetylenic Hydrogen

Highly Flammable

ACETYLENE reacts with alkali metals, forming hydrogen gas. Acetylene can react explosively with bromine [Von Schwartz 1918. p.142]. Acetylene forms a sensitive acetylide when passed into an aqueous solution of mercuric nitrate [Mellor 4:933. 1946-47]. It reacts with silver, copper and lead to form sensitive, explosive salts. Since acetylene is endothermic and effectively a reducing agent, its reaction with oxidants can be very violent (examples: calcium hypochlorite, nitric acid, nitrogen oxide, ozone, trifluoromethyl hypofluorite, etc.). Contact of very cold liquefied gas with water may result in vigorous or violent boiling of the product and extremely rapid vaporization, due to the large temperature differences involved. If the water is hot, there is the possibility that a liquid "superheat" explosion may occur. Pressures may build to dangerous levels if liquid gas contacts water in a closed container [Handling Chemicals Safely 1980]. Acetylene and ammonia can form explosive silver salts in contact with Ag. (Renner, Hermann, Gunther Schlamp. "Silver, Silver Compounds, and Silver Alloys." Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH Verlag GmbH & Co. KGaA. 2001.).

Mixture with air containing between 3-82% gas is explosive. Contact with /bleaching powder may lead to formation of explosive chloroacetylenes. Finely divided /cobalt/ metal decomposes and polymerizes acetylene on contact, becoming incandescent. Copper metal forms explosive compounds with acetylene. If warmed in air or oxygen, or on impact, copper acetylides may explode in subsequent contact with acetylene. Interaction with /halogens/ can be violent or explosive. Contact of acetylene with concentrated nitric acid in presence of mercury forms explosive trinitromethane or tetranitromethane if sulfuric acid is subsequently added. Mixture with /nitric oxide products/ will ignite at +30-50 °C. Mixtures with /oxygen/ are very explosive even at very low oxygen concentrations (<2.5%). Molten /potassium/ ignites in acetylene, then explodes. /Silver/ forms explosive compounds with acetylene. Interaction with /trifluoromethyl hypofluorite/, in absence of nitrogen as diluent, is explosive on mixing.

Contact of acetylene with the concn /nitric/ acid in presence of mercury (II) salts forms trinitromethane, explosive above its mp, 15 °C. Subsequent addition of sulfuric acid produces tetranitromethane, a powerful oxidant of limited stability, in high yield.

Care is necessary with acetylene-fed atomic absorption spectroscopy (AAS) burners to prevent air being drawn up the liquid drainage line, when explosion is likely. While setting up an AAS instrument for use with nitrous oxide-acetylene, an explosion occurred shortly after switching from compressed air to the oxide, when the flame became unstable. This was attributed to the outdoor location of the nitrous oxide cylinder (at 5 °C) and the expansion cooling (4 °C) occurring in the reducing valve, combining to reduce the oxide flow to the point of flame instability and flashback. It was proposed that in student laboratories, air-acetylene flame sources should be replaced by air-natural gas flames to improve safety aspects with very little fall-off in detection limits in instrumental AA metal determinations. Three further incidents involving explosions in AAS installations are reported, one involved accidental contamination of the acetylene inlet line by liquid acetone from an overfilled acetylene cylinder. The other explosions involved leakage of acetylene gas inside the instrument cases and ignition by the electrical controls. Fitting of acetylene sensors inside such instruments to prevent further incidents is suggested. Acetylene gas leaking from a supply tube was ignited by the source flame and a minor explosion occurred, and appears to have damaged both gas supply lines, which led to a second major explosion and fire. This involved some 6 cu m of acetylene and 18 cu m of nitrous oxide, and caused severe structural damage.

A number of explosions have been experienced when using sample soln containing perchloric acid in atomic absorption spectrometers using acetylene-nitrous oxide flames ...

For more Hazardous Reactivities and Incompatibilities (Complete) data for ACETYLENE (37 total), please visit the HSDB record page.

Zinc; oxygen & other oxidizing agents such as halogens [Note: Forms explosive acetylide compounds with copper, mercury, silver & brasses (containing more than 66% copper).]

The substance can be absorbed into the body by inhalation.

inhalation, skin and/or eye contact (liquid)

Dizziness. Lethargy. Headache. Suffocation.

headache, dizziness; asphyxia; liquid: frostbite

central nervous system, respiratory system

Neurotoxin - Acute solvent syndrome

Other Poison - Simple Asphyxiant

/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.

Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Aliphatic hydrocarbons and related compounds/

Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool. Administer activated charcoal ... . Treat frostbite with rapid rewarming techniques ... ./Aliphatic hydrocarbons and related compounds/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag-valve-mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously.Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Aliphatic hydrocarbons and related compounds/

Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Simple asphyxiants and related compounds/

For more Antidote and Emergency Treatment (Complete) data for ACETYLENE (6 total), please visit the HSDB record page.

/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, headache; 40% 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.

/LABORATORY ANIMALS: Acute Exposure/ In rats, a concentration of 78% acetylene (780,000 ppm) produced anesthesia in 15 minutes, and inhalation of 90% for 2 hours caused respiratory failure ...

/LABORATORY ANIMALS: Acute Exposure/ Rabbits were exposed to acetylene/oxygen mixtures containing up to 700,000 ppm acetylene. After 17 min saturation of the blood acetylene concn was reached. Acetylene did not impair the oxygen content in the arterial blood, but the carbon dioxide tension was decreased. Increased respiration was observed after anesthesia.

/LABORATORY ANIMALS: Acute Exposure/ ... The effects of acetylene anesthesia on carbohydrate and acid-base regulation in the blood of dogs which had been admin acetylene at a concn of 800000 ppm in oxygen for 1 hr /were studied/. The following observations were made: a decrease in the alkali reserve and carbonic acid concn, an increase during and a fall after anesthesia in both the oxygen-binding capacity of the blood and the arterial-oxygen deficit. A slight decrease in blood sugar levels during anesthesia.

/LABORATORY ANIMALS: Acute Exposure/ Male Wistar rats were exposed to 5% acetylene for 18 hr. This treatment caused loss of heme and a marked accumulation of porphyrins in the liver. Metabolic activation of acetylene was necessary for the loss of microsomal cytochrome P450.

For more Non-Human Toxicity Excerpts (Complete) data for ACETYLENE (17 total), please visit the HSDB record page.

LC50; Species: Salmo fario (river trout); Concentration: 200 mg/L for 33 hr /Conditions of bioassay not specified/

Acetylene's production and use as an illuminant, oxyacetylene welding, cutting, and soldering metals, signaling, in precipitating metals, particularly copper, in the manufacture of acetaldehyde and acetic acid may result in its release to the environment through various waste streams. Acetylene is released from burning wood. If released to air, a vapor pressure of 3.65X10+4 mm Hg at 25 °C indicates acetylene will exist solely as a gas in the atmosphere. Gas-phase acetylene will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 20 days. Acetylene has a calculated global lifetimes ranging from 14 to 32 days in the atmosphere. Acetylene does not contain chromophores that absorb at wavelengths >290 nm and, therefore, is not expected to be susceptible to direct photolysis by sunlight. If released to soil, acetylene is expected to have very high mobility based upon an estimated Koc of 2. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 2.2X10-2 atm-cu m/mole. Acetylene will volatilize from dry soil surfaces based upon its vapor pressure. Utilizing the Japanese MITI test, 0% of the Theoretical BOD was reached in 4 weeks indicating that biodegradation is not an important environmental fate process in soil or water. If released into water, acetylene is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 1.5 hours and 2 days, respectively. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions (pH 5 to 9). Occupational exposure to acetylene may occur through inhalation and dermal contact with this compound at workplaces where acetylene is produced or used. Monitoring data indicate that the general population may be exposed to acetylene via inhalation due to the release of this substance from combustion fuels, use of acetylene torches during welding, soldering and other metal work and through inhalation of cigarette and wood smoke. (SRC)

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).

Acetylene's production and use as an illuminant, oxyacetylene welding, cutting, and soldering metals, signaling, in precipitating metals, particularly copper, in the manufacture of acetaldehyde, acetic acid, and in fuel for motor boats(1) may result in its release to the environment through various waste streams(SRC).

Manmade sources: diesel engine: 14.1% of emitted hydrocarbons; reciprocating gasoline engine: 12-17% of emitted hydrocarbons; rotary gasoline engine: 3.3% of emitted hydrocarbons

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).

AEROBIC: Acetylene, present at 1.6 mg/L, reached 0% of its theoretical BOD in 28 days using an activated sludge inoculum in the Japanese MITI test(1).

PURE CULTURE: Pure cultures of Rhodococcus A1 have been show to metabolize acetylene; the major metabolite from this biodegradation is acetaldehyde(1,2).

The rate constant for the vapor-phase reaction of acetylene with photochemically-produced hydroxyl radicals is 8.15X10-13 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 20 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the vapor-phase reaction of acetylene with ozone has been estimated as 3X10-20 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(1). This corresponds to an atmospheric half-life of about 382 days at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(2). Acetylene has a calculated global lifetime of 32 days in the atmosphere(3). Acetylene is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(4). Acetylene does not contain chromophores that absorb at wavelengths >290 nm and, therefore, is not expected to susceptible to direct photolysis by sunlight(4).

An estimated BCF of 3 was calculated in fish for acetylene(SRC), using a log Kow of 0.37(1) and a regression-derived equation(2). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

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).

LC50; Species: Salmo fario (river trout); Concentration: 200 mg/L for 33 hr /Conditions of bioassay not specified/

Acetylene's production and use as an illuminant, oxyacetylene welding, cutting, and soldering metals, signaling, in precipitating metals, particularly copper, in the manufacture of acetaldehyde and acetic acid may result in its release to the environment through various waste streams. Acetylene is released from burning wood. If released to air, a vapor pressure of 3.65X10+4 mm Hg at 25 °C indicates acetylene will exist solely as a gas in the atmosphere. Gas-phase acetylene will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 20 days. Acetylene has a calculated global lifetimes ranging from 14 to 32 days in the atmosphere. Acetylene does not contain chromophores that absorb at wavelengths >290 nm and, therefore, is not expected to be susceptible to direct photolysis by sunlight. If released to soil, acetylene is expected to have very high mobility based upon an estimated Koc of 2. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 2.2X10-2 atm-cu m/mole. Acetylene will volatilize from dry soil surfaces based upon its vapor pressure. Utilizing the Japanese MITI test, 0% of the Theoretical BOD was reached in 4 weeks indicating that biodegradation is not an important environmental fate process in soil or water. If released into water, acetylene is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 1.5 hours and 2 days, respectively. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions (pH 5 to 9). Occupational exposure to acetylene may occur through inhalation and dermal contact with this compound at workplaces where acetylene is produced or used. Monitoring data indicate that the general population may be exposed to acetylene via inhalation due to the release of this substance from combustion fuels, use of acetylene torches during welding, soldering and other metal work and through inhalation of cigarette and wood smoke. (SRC)

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).

Acetylene's production and use as an illuminant, oxyacetylene welding, cutting, and soldering metals, signaling, in precipitating metals, particularly copper, in the manufacture of acetaldehyde, acetic acid, and in fuel for motor boats(1) may result in its release to the environment through various waste streams(SRC).

Manmade sources: diesel engine: 14.1% of emitted hydrocarbons; reciprocating gasoline engine: 12-17% of emitted hydrocarbons; rotary gasoline engine: 3.3% of emitted hydrocarbons

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).

AEROBIC: Acetylene, present at 1.6 mg/L, reached 0% of its theoretical BOD in 28 days using an activated sludge inoculum in the Japanese MITI test(1).

PURE CULTURE: Pure cultures of Rhodococcus A1 have been show to metabolize acetylene; the major metabolite from this biodegradation is acetaldehyde(1,2).

The rate constant for the vapor-phase reaction of acetylene with photochemically-produced hydroxyl radicals is 8.15X10-13 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 20 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the vapor-phase reaction of acetylene with ozone has been estimated as 3X10-20 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(1). This corresponds to an atmospheric half-life of about 382 days at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(2). Acetylene has a calculated global lifetime of 32 days in the atmosphere(3). Acetylene is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(4). Acetylene does not contain chromophores that absorb at wavelengths >290 nm and, therefore, is not expected to susceptible to direct photolysis by sunlight(4).

An estimated BCF of 3 was calculated in fish for acetylene(SRC), using a log Kow of 0.37(1) and a regression-derived equation(2). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

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).

The Henry's Law constant for acetylene is estimated as 2.2X10-2 atm-cu m/mole(SRC) derived from its vapor pressure, 3.65X10+4 mm Hg(1), and water solubility, 1,200 mg/L(2). This Henry's Law constant indicates that acetylene is expected to volatilize rapidly from water surfaces(3). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(3) is estimated as 1.5 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(3) is estimated as 2 days(SRC). Acetylene's estimated Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). The potential for volatilization of acetylene from dry soil surfaces will exist(SRC) based upon its vapor pressure(1).

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).

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 ppb

RURAL/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).

Acetylene was released from lignin samples at concentrations ranging from 90-2,900 mg/kg(1). Fine particle emissions of acetylene from burning of Lobolly pine, Western Hemlock, Ponderosa pine (Pinaceae) were 112.3, 55.1, and 114.2 mg/kg biomass burned. Mass emission rates of 80.1, 80.8, and 71.1 mg/kg biomass burned were reported for Aceraceae/Fagaceae, Palmae/Pinaceae, and Poaceae/Pinaceae, respectively(2). Acetylene is released from burning wood in fireplaces and stoves at concentrations 313-540 and 1119 mg/kg(3).

Acetylene is one of the breakdown products of volatile substances in curing smoke which originate from the thermal decomposition of cellulose, lignin and hemicullulose into methylene radicals and hydrogen. The methylene radical dimerises to ethylene, which further breaks down to hydrogen and acetylene; the latter partly decomposes to carbon, hydrogen, and methane and partly polymerizes to polynuclears with further loss of hydrogen(1).

According to the 2006 TSCA Inventory Update Reporting data, the number of persons reasonably likely to be exposed in the industrial manufacturing, processing, and use of acetylene is 1000 or greater; the data may be greatly underestimated(1).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 48,962 workers (3,072 of these were female) were potentially exposed to acetylene in the US(1). Occupational exposure to acetylene may occur through inhalation and dermal contact with this compound at workplaces where acetylene is produced or used. Monitoring data indicate that the general population may be exposed to acetylene via inhalation due to the release of this substance from combustion fuels, use of acetylene torches during welding, soldering and other metal work and through inhalation of cigarette and wood smoke(SRC).

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 quality; potential migration in soil or water; effects on animal and plant life; and 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.

/GUIDE 116: GASES - FLAMMABLE (Unstable)/ Fire or Explosion: EXTREMELY FLAMMABLE. Will be easily ignited by heat, sparks or flames. Will form explosive mixtures with air. Silane will ignite spontaneously in air. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Vapors from liquefied gas are initially heavier than air and spread along ground. Vapors may travel to source of ignition and flash back. Cylinders exposed to fire may vent and release flammable gas through pressure relief devices. Containers may explode when heated. Ruptured cylinders may rocket.

/GUIDE 116: GASES - FLAMMABLE (Unstable)/ Health: Vapors may cause dizziness or asphyxiation without warning. Some may be toxic if inhaled at high concentrations. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire may produce irritating and/or toxic gases.

/GUIDE 116: GASES - FLAMMABLE (Unstable)/ Public Safety: CALL Emergency Response Telephone Number on Shipping Paper first. If Shipping Paper not available or no answer, refer to appropriate telephone number listed on the inside back cover. As an immediate precautionary measure, isolate spill or leak area for at least 100 meters (330 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Many gases are heavier than air and will spread along ground and collect in low or confined areas (sewers, basements, tanks). Keep out of low areas.

/GUIDE 116: GASES - FLAMMABLE (Unstable)/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Structural firefighters' protective clothing will only provide limited protection.

For more DOT Emergency Guidelines (Complete) data for ACETYLENE (8 total), please visit the HSDB record page.

UN 1001; Acetylene, dissolved

IMO 2.1; Acetylene, dissolved

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.

Acetylene (liquefied) has a hazard class of "forbidden." Quantity limitations for acetylene, dissolved: Shipment of dissolved acetylene forbidden in passenger aircraft or railcar; under certain conditions a limit of 15 kg may be shipped by cargo aircraft.

Flammable Gas

Special insulated cylinder.

Symbol: F+; R: 5-6-12; S: (2)-9-16-33

UN Hazard Class: 2.1