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SECTION 1. CHEMICAL IDENTIFICATION

CHEMINFO Record Number: 72
CCOHS Chemical Name: Ethane

Synonyms:
Bimethyl
Dimethyl
Ethyl hydride
Methylmethane

Chemical Name French: Éthane
Chemical Name Spanish: Etano
CAS Registry Number: 74-84-0
UN/NA Number(s): 1035
RTECS Number(s): KH3800000
EU EINECS/ELINCS Number: 200-814-8
Chemical Family: Saturated aliphatic hydrocarbon / paraffin / n-alkane / ethane
Molecular Formula: C2-H6
Structural Formula: CH3-CH3

SECTION 2. DESCRIPTION

Appearance and Odour:
Colourless, odourless gas. May have a mild gasoline-like or sweet odour depending on the impurities present.(1,5)

Odour Threshold:
Odourless (1,16)

Warning Properties:
NONE - compound is odourless.

Composition/Purity:
Technical and higher grades of ethane are at least 95% pure. These grades contain trace impurities such as nitrogen, hydrogen, oxygen, water, carbon dioxide, ethylene, acetylene, propane, propylene, butane and its isomers.(5,18)

Uses and Occurrences:
Ethane is used as a fuel, and refrigerant and in the manufacture ethylene.(5,19 ) The main source of ethane is natural gas, which is essentially of biological origin and is found in geological gas reservoirs, crude oil wells and coal mines.(19)


SECTION 3. HAZARDS IDENTIFICATION

EMERGENCY OVERVIEW:
Colourless, odourless gas. EXTREMELY FLAMMABLE GAS. COMPRESSED GAS or REFRIGERATED LIQUEFIED GAS. Gas is slightly heavier than air and may spread long distances. Distant ignition and flash back are possible. Essentially non-toxic at low concentrations. Asphyxiant. At high concentrations, ethane gas reduces oxygen available for breathing. Confined space hazard. Can accumulate in confined spaces, producing a fire and asphyxiation hazard. Rapid evaporation of liquefied gas from cylinder can cause cold burns or frostbite.



POTENTIAL HEALTH EFFECTS

Effects of Short-Term (Acute) Exposure

Inhalation:
Ethane is relatively non-toxic below the lower explosive limit of 3% (30000 ppm).
When ethane is present in high concentrations in the air it acts as an asphyxiant. Asphyxiants displace oxygen and can cause symptoms of oxygen deprivation (asphyxiation). The available oxygen should be a minimum of 18% or harmful effects will result.(3,11) Ethane displaces oxygen to 18% in air when present at 14% (140000 ppm). However, it is expected to cause unconsciousness (narcosis) due to central nervous system depression at slightly lower concentrations (13% or 130000 ppm) - still well above the lower explosive limit.(13) Other symptoms of central nervous system depression are headache, nausea, vomiting and dizziness.
Effects of oxygen deficiency are: 12-16% - breathing and pulse rate are increased, with slight muscular incoordination; 10-14% - emotional upsets, abnormal fatigue from exertion, disturbed respiration; 6-10% - nausea and vomiting, inability to move freely, collapse, possible lack of consciousness; below 6% - convulsive movements, gasping, possible respiratory collapse and death. Since exercise increases the body's need for oxygen, symptoms will occur more quickly during exertion in an oxygen-deficient environment.(3,11) Survivors of oxygen deprivation may show damage to some or all organs including the central nervous system and the brain. These effects may or may not be reversible with time, depending on the degree and duration of the low oxygen and the amount of tissue injury.(3)
Some closely related aliphatic hydrocarbons (propane, butane and isobutane) may be weak cardiac sensitizers in humans following inhalation exposures to high concentrations (greater than 5% for isobutane and greater than 10% for propane). Cardiac sensitizers may cause the sudden onset of an irregular heartbeat (arrhythmia) and, in some cases, sudden death. Sudden deaths have been reported in cases of substance abuse involving butane and propane. Under stressful conditions and with exposure to high concentrations, the effects of cardiac sensitization may be important for some hydrocarbon gases. The asphyxiant effects of ethane may enhance cardiac sensitization.(12)

Skin Contact:
Ethane gas is not a skin irritant.
Contact with refrigerated liquefied gas or compressed gas may cause cold burns or frostbite. Symptoms of mild frostbite include numbness, prickling and itching in the affected area. Symptoms of more severe frostbite include a burning sensation and stiffness of the affected area. The skin may become waxy white or yellow. Blistering, tissue death and gangrene may also develop in severe cases.

Eye Contact:
Ethane gas is not an eye irritant.
Direct contact with refrigerated liquefied gas or compressed gas may cause cold burns or freezing of the eye. Permanent eye damage or blindness could result.

Ingestion:
Not applicable to gases.

Effects of Long-Term (Chronic) Exposure

No human or animal information was located. Harmful effects are not expected following long-term exposure.

Carcinogenicity:

No human or animal information was located. Ethane is not expected to cause cancer.

The International Agency for Research on Cancer (IARC) has not evaluated the carcinogenicity of this chemical.

The American Conference of Governmental Industrial Hygienists (ACGIH) has not assigned a carcinogenicity designation to this chemical.

The US National Toxicology Program (NTP) has not listed this chemical in its report on carcinogens.

Teratogenicity and Embryotoxicity:
No human or animal information was located. Ethane is not expected to cause developmental toxicity.

Reproductive Toxicity:
No human or animal information was located. Ethane is not expected to cause reproductive toxicity.

Mutagenicity:
No relevant information was located. Ethane is not expected to be mutagenic.

Toxicologically Synergistic Materials:
No information was located.

Potential for Accumulation:
Does not accumulate. Rapidly eliminated unchanged.


SECTION 4. FIRST AID MEASURES

Inhalation:
This is chemical is extremely flammable. Take proper precautions (e.g. remove any sources of ignition). In general, this gas has very low toxicity, but it can act as an asphyxiant at high concentrations. If the victim has been knocked down, wear appropriate protective equipment, and use the buddy system. Remove source of contamination or move victim to fresh air. If breathing is difficult, oxygen may be beneficial if administered by trained personnel, preferably on a doctor's advice. If breathing has stopped, trained personnel should begin artificial respiration (AR) or, if the heart has stopped, cardiopulmonary resuscitation (CPR) immediately. Immediately transport victim to an emergency care facility.

Skin Contact:
REFRIGERATED LIQUEFIED GAS OR COMPRESSED GAS: Quickly remove victim from source of contamination and briefly flush with lukewarm, gently flowing water until the chemical is removed. DO NOT attempt to rewarm the affected area on site. DO NOT rub area or apply dry heat. Gently remove clothing or jewelry that may restrict circulation. Carefully cut around clothing that sticks to the skin and remove the rest of the garment. Loosely cover the affected area with a sterile dressing. DO NOT allow victim to drink alcohol or smoke. Quickly transport victim to an emergency care facility. GAS: Not applicable. No effects expected.

Eye Contact:
REFRIGERATED LIQUEFIED GAS OR COMPRESSED GAS: Quickly remove victim from source of contamination. Immediately and briefly flush with lukewarm, gently flowing water until the chemical is removed. DO NOT attempt to rewarm. Cover both eyes with a sterile dressing. DO NOT allow victim to drink alcohol or smoke. Quickly transport victim to an emergency care facility. GAS: Not applicable. No effects expected.

Ingestion:
Ingestion is not an applicable route of exposure for gases.

First Aid Comments:
Provide general supportive measures (comfort, warmth, rest).
Consult a doctor and/or the nearest Poison Control Centre for all exposures except minor instances of inhalation or skin contact. Some recommendations in the above sections may be considered medical acts in some jurisdictions. These recommendations should be reviewed with a doctor and appropriate delegation obtained, as required.
All first aid procedures should be periodically reviewed by a doctor familiar with the material and its condition of use in the workplace.



SECTION 5. FIRE FIGHTING MEASURES

Flash Point:
Flammable gas

Lower Flammable (Explosive) Limit (LFL/LEL):
3.0% (6)

Upper Flammable (Explosive) Limit (UFL/UEL):
12.5% (6)

Autoignition (Ignition) Temperature:
472 deg C (882 deg F) (6)

Sensitivity to Mechanical Impact:
Not sensitive.

Sensitivity to Static Charge:
Liquefied ethane can accumulate electrostatic charge by flow, friction in pipes, splashing or agitation. Ethane gas in the flammable range can be easily ignited by an electrostatic discharge of sufficient energy (e.g. brush discharge).

Electrical Conductivity:
Not applicable for gas. Not available for liquefied gas. The electric conductivity for liquefied ethane is expected to be less then 50 pS/m, based on ethane's chemical properties and dielectric constant.

Minimum Ignition Energy:
0.24 mJ for 6.5% by volume (6)

Combustion and Thermal Decomposition Products:
Carbon monoxide, carbon dioxide, and water.

Fire Hazard Summary:
EXTREMELY FLAMMABLE COMPRESSED GAS OR REFRIGERATED LIQUEFIED GAS. Can readily form explosive mixtures with air, which are easily ignited by a static charge. Liquefied gas accumulates static charge. Liquefied ethane gas vapourizes under normal conditions and produces 250 volumes vapour for every one volume of liquid. A major release of liquefied ethane will produce a large vapour cloud due to condensation of moisture. Small spills of liquefied ethane will tend to rise and diffuse rapidly above the leak. However, the gas is slightly heavier than air and may travel long distances. Large spills of liquefied ethane very rapidly form dense flammable vapours which will travel over long distances and will create a flash back hazard. Direct addition of water (or any other room temperature liquid) to the liquefied gas will cause flash vapourization resulting in an explosion (either immediate or delayed) known as a "boiling liquid, expanding vapour explosion (BLEVE)".(23,24) The gas can accumulate in confined spaces, resulting in explosion and asphyxiaytion hazards. During a fire, toxic gases may be generated. Heat from a fire can cause a rapid build-up of pressure inside cylinders or tanks, which may cause explosive rupture and a sudden release of large amounts of extremely flammable gas.

Extinguishing Media:
Dry chemical powder and high-expansion foam. Foam manufacturers should be consulted for recommendations regarding types of foams and application rates.(23,24)

Extinguishing Media to be Avoided:
Carbon dioxide, low expansion foams, and direct application of water on liquefied ethane gas. Under certain conditions, discharge of carbon dioxide produces electrostatic charges that could create a spark and ignite ethane.(23,25)

Fire Fighting Instructions:
Evacuate area. Fight fire from a protected location or maximum distance possible. Approach fire from upwind to avoid toxic decomposition products.
For fires involving flammable gases, the best procedure is to stop the flow of gas before attempting to extinguish the fire. It is extremely dangerous to extinguish the fire, while allowing continued flow of the gas. The gas could form an explosive mixture with air and re-ignite resulting in a sudden violent flash fire, which may cause far more damage than if the original fire had been allowed to burn. In some cases, extinguishing the fire with dry chemical powder may be necessary to permit immediate access to valves to shut off the flow of gas. However, this must be done carefully. If it is not possible to stop the flow of gas and if there is no risk to the surrounding area, allow the fire to continue burning while protecting exposed materials with water spray, to prevent ignition of other combustible materials.
DO NOT direct water spray into liquefied gas. Liquefied ethane gas spill clouds may be controlled with high-expansion foam blankets. The resulting foam solutions may be flammable. Dike for appropriate disposal. Cryogenic liquids can be particularly dangerous during fires because of their potential to rapidly freeze water. Avoid spraying cold areas of containers or equipment to avoid rapid freezing of water, which can result in heavy icing and possible blockage of pressure release valves.
Heat from a fire can cause a rapid build-up of pressure inside cylinders or tanks, which may cause explosive rupture. Withdraw immediately in case of rising sound from venting safety device or any discolouration of tank due to fire.
Cool fire-exposed cylinders, tanks, equipment or pipelines by applying hose streams, to minimize the risk of rupture. Cooling should begin as soon as possible (within several minutes) and should concentrate on any unwetted portions of the container. Apply water from the side and a safe distance. DO NOT direct water at open or leaking cylinders and take precautions not to get water inside a container or cylinder. Reverse flow into cylinder may cause rupture. No part of a cylinder should be subjected to a temperature higher than 52 deg C (approximately 125 deg F). Cooling should continue until well after the fire is out.
Isolate cylinders and other containers exposed to heat but not yet directly involved in the fire and protect personnel. Move cylinders from fire area only if this can be done without risk. Stay away from ends of tanks, but be aware that flying material (shrapnel) from ruptured tanks or cylinders may travel in any direction.
For an advanced or a massive fire in a large area, use unmanned hose holder or monitor nozzles; if this is not possible withdraw from fire area and allow fire to burn.
After the fire has been extinguished, the resulting foam solutions of ethane are flammable. Explosive atmospheres may be present. Before entering such an area, especially confined areas, check the atmosphere with an appropriate monitoring device. Cylinders or tanks that have been involved in a fire should not be approached until they have been completely cooled down.

Protection of Fire Fighters:
Ethane is only slightly hazardous to health. However, it can displace oxygen, reducing the amount available for breathing. Firefighters may enter the area if positive pressure self-contained breathing apparatus (NIOSH approved or equivalent) and full Bunker Gear is worn.



NATIONAL FIRE PROTECTION ASSOCIATION (NFPA) HAZARD IDENTIFICATION

NFPA - Health: 1 - Exposure would cause significant irritation, but only minor residual injury.
NFPA - Flammability: 4 - Will rapidly or completely vaporize at atmospheric pressure and normal ambient temperature, or readily disperse in air and burn readily.
NFPA - Instability: 0 - Normally stable, even under fire conditions, and not reactive with water.

SECTION 9. PHYSICAL AND CHEMICAL PROPERTIES

Molecular Weight: 30.07

Conversion Factor:
1 ppm = 1.23 mg/m3; 1 mg/m3 = 0.81 ppm at 25 deg C (calculated)

Physical State: Gas
Melting Point: -183 deg C (-297.4 deg F) (20)
Boiling Point: -88.6 deg C (-127.5 deg F) (20)
Relative Density (Specific Gravity): Not applicable (gas)
Solubility in Water: Practically insoluble (60 mg/L) at 25 deg C (20)
Solubility in Other Liquids: Ethane is expected to be soluble in non-polar solvents such as benzene, carbon tetrachloride and ether, and is not expected to be soluble in polar solvents such as methanol.
Coefficient of Oil/Water Distribution (Partition Coefficient): Log P(oct) = 1.81 (20)
pH Value: Not applicable
Vapour Density: 1.037 (air = 1) (calculated)
Vapour Pressure: 4190 kPa (31500 mm Hg) at 21 deg C (20)
Vapour Pressure at 50 deg C: 5600 kPa (55 atm) (estimated from graph) (1)
Saturation Vapour Concentration: Not applicable (gas)
Evaporation Rate: Not applicable for gas. Refrigerated liquefied ethane will evaporate rapidly at room temperature.
Henry's Law Constant: 5.07 X 10(4) Pa.m3/mol (cited as 0.5 atm.m3/mol) at 25 deg C (20); log H = 1.31 (dimensionless constant; calculated)
Critical Temperature: 32.3 deg C (90.1 deg F) (21)
Critical Pressure: 4872 kPa (48.1 atm) (21)

Other Physical Properties:
DIELECTRIC CONSTANT: 1 at deg 21 deg C (dimensionless) (22)


SECTION 10. STABILITY AND REACTIVITY

Stability:
Stable.

Hazardous Polymerization:
Does not occur.

Incompatibility - Materials to Avoid:

NOTE: Chemical reactions that could result in a hazardous situation (e.g. generation of flammable or toxic chemicals, fire or detonation) are listed here. Many of these reactions can be done safely if specific control measures (e.g. cooling of the reaction) are in place. Although not intended to be complete, an overview of important reactions involving common chemicals is provided to assist in the development of safe work practices.


The risk of a hazardous incident occurring due to accidental mixing of ethane with other substances is low because ethane only reacts with a very small number of chemical classes that are commonly used in the workplace. If an accidental mixing does occur, these few reactions may be severe.

STRONG OXIDIZING AGENTS (e.g. peroxides, perchlorates) - Increases the risk of fire and explosion. Reaction may be delayed.(19)
HALOGEN COMPOUNDS (e.g. chlorine, and bromine) - Risk of fire and explosion. Fluorine gas reacts explosively.(26) Mixtures with 20% or more of chlorine are explosive. However, if any mixture of ethane and chlorine gas is exposed to direct sunlight there is almost always an explosion.(27) The presence of some metallic salts or oxides (e.g. ferric chloride, copper oxide) or metals (e.g. mercury, zinc) increases the reactivity with the halogen compounds.(27,28) Reaction with iodine is not vigorous.(29)

Hazardous Decomposition Products:
None

Conditions to Avoid:
Static charge, sparks, open flames and other ignition sources

Corrosivity to Metals:
Pure ethane gas is not corrosive to aluminum or carbon steel.(30)

Corrosivity to Non-Metals:
Pure ethane gas is corrosive to acrylonitrile butadiene styrene(ABS), high density polyethylene (HDPE), polyvinyl chloride(PVC), polyproylene, polyamides, and polyurethane. Ethane gas is not corrosive to fluorinated plastics, ultra high molecular weight polyethylene, and polyacetals.(31)


SECTION 11. TOXICOLOGICAL INFORMATION

No standard animal toxicity values are available.

Effects of Short-Term (Acute) Exposure:

Inhalation:
In a limited historical study, guinea pigs (3/group) were exposed to 2.2-2.7% (22000-27000 ppm) or 4.7-5.5% (47000-55000 ppm) for 5 minutes, 30 minutes, 1 hour or 2 hours. The animals appeared normal with exposure to 2.2-2.3% for 5 minutes. Somewhat irregular breathing was noted with exposure to 2.2-2.7% for 30 minutes or 1 hour. Animals exposed for 2 hours appeared somewhat drowsy, responded slowly to sound and their breathing rate was somewhat rapid. Slightly fast and/or irregular breathing was noted with exposure to 4.7-5.5% for 5 or 30 minutes. Animals exposed for 1 or 2 hours were dazed, responded slowly to sound, and had irregular breathing. All animals recovered quickly and appeared normal during a 10-day observation period. Autopsy of one animal exposed to 4.7-5.5% for 2 hours showed no effects.(15) Exposure to 15-90% (150000-900000 ppm) ethane mixed with oxygen caused weak cardiac sensitization in 2/4 dogs injected with epinephrine.(14) This study is limited by the small number of animals used and incomplete reporting. No signs of anesthesia were observed in animals (species unspecified) breathing an ethane:oxygen mixture (3.5 or 5 volumes ethane with 1 volume oxygen) for 1-3.75 hours.(2, unconfirmed) There are no further details available for evaluation.


SECTION 16. OTHER INFORMATION

Selected Bibliography:
(1) Yaws, C.L. Matheson gas data book. 7th ed. McGraw-Hill, 2001. p. 346-349
(2) Von Oettingen, W.F. Toxicity and potential dangers of aliphatic and aromatic hydrocarbons : a critical review of the literature. Public Health Bulletin. No. 255. US Public Health Services, 1940. p. 2-3
(3) Wilkenfeld, M. Simple asphyxiants. In: Environmental and Occupational Medicine. 3rd ed. Edited by W.N. Rom. Lippincott-Raven Publishers, 1998. p. 651-655
(4) Low, L.K., et al. Ethane. In: Ethel Browning's toxicity and metabolism of industrial solvents. 2nd ed. Vol. 1 : hydrocarbons. Elsevier, 1987. p. 258-260
(5) Compressed Gas Association. Handbook of compressed gases. 4th ed. Kluwer Academic Publishers, 1999. p. 345-350
(6) Fire protection guide to hazardous materials. 13th ed. Edited by A.B. Spencer, et al. National Fire Protection Association, 2002. NFPA 325
(7) NIOSH pocket guide to chemical hazards. NIOSH, June 1994. p. 262-263
(8) Forsberg, K., et al. Quick selection guide to chemical protective clothing. 4th ed. Van Nostrand Reinhold, 2002
(9) European Communities (EC). Commission Directive 93/72/EC. Sept. 1, 1993
(10) Careon, T. Aliphatic hydrocarbons. In: Patty's toxicology. 5th ed. Edited by E. Bingham, et al. Vol. 4. John Wiley and Sons, 2001
(11) Leikauf, G.D., et al. Inorganic compounds of carbon, nitrogen and oxygen. In: Patty's Toxicology. 5th ed. Edited by E. Bingham, et al. Vol. 3. John Wiley & Sons, 2001
(12) Aliphatic hydrocarbon gases: alkanes (C1-C4). In: Documentation of threshold limit values and biological exposure indices. 7th ed. (Suppl.). American Conference of Governmental Industrial Hygienists, 2004
(13) Drummond, I. Light hydrocarbon gases: a narcotic, asphyxiant, or flammable hazard? Applied Occupational and Environmental Hygiene. Vol. 8 (1993). p. 120-125
(14) Krantz, Jr., J.C., et al. Anesthesia. XXXI. A study of cyclic and noncyclic hydrocarbons on cardiac automaticity. Journal of Pharmacology and Experimental Therapeutics. Vol. 94 (1948). p. 315-318
(15) Nuckolls, A.H. Underwriters' Laboratories' report on the comparative life, fire and explosion hazard of common refrigerants. Miscellaneous Hazard No. 2375. For: Kinetic Chemicals, Inc. Underwriters' Laboratories, Nov. 13, 1933
(16) Odor thresholds for chemicals with established occupational health standards. American Industrial Hygiene Association, 1989. p. 18
(17) Ruth, J.H. Odor thresholds and irritation levels of several chemical substances: a review. American Industrial Hygiene Association Journal. Vol. 47 (1986). p. A142-A151
(18) Ethane. Matheson Tri*Gas Website. Matheson Tri*Gas. Specification sheet. Available at:
<www.matheson-trigas.com/mathportal/catalog/index.cfm>
(19) Mears, D.E. et al. Hydrocarbons. In: Kirk-Othmer encyclopedia of chemical technology. Available at: <www.mrw.interscience.wiley.com/kirk/articles/survmear.a01/sect3-fs.html> {Subscription required}
(20) Syracuse Research Corporation. The Physical Properties Database (PHYSPROP). Interactive PhysProp Database Demo. Date unknown. Available at: <www.syrres.com/esc/physdemo.html>
(21) Lide, D.R., ed. Handbook of chemistry and physics. 82nd ed. CRC Press, 2001. p. 3-152
(22) Smyth, C.P. et al. The dielectric constants of ethane, ethylene, acetylene and butylene, and the symmetry of unsaturated bonds. Journal of the American Chemical Society. Vol. 47, no. 10 (1925). p. 2501-2506
(23) Recommended practice for responding to hazardous materials incidents. National Fire Protection Association, 2002. NFPA 471
(24) A guide to the safe handling of hazardous materials accidents. 2nd ed. Manual 10. American Society for Testing and Materials (ASTM), 1990
(25) Standard on carbon dioxide extinguishing systems. National Fire Protection Association, 2000. NFPA 12, Section 1-5.2.2
(26) Hauge, R.H. et al. Studies of the reaction of molecular fluorine with methane, acetylene, ethylene, allene, and other small hydrocarbons in matrices at low temperatures. Journal of the American Chemical Society. Vol. 101, no. 23 (1979). p. 6950
(27) Egloff, G. The halogenation of the paraffin hydrocarbons. Chemical Reviews. Vol. 8, no. 1 (1930). p. 1-80
(28) Steacie, E.W.R. The kinetics of elementary reactions of the simple hydrocarbons. Chemical Reviews. Vol. 22, no. 2. (1938). p. 311-402
(29) Thomas, C.L. et al. Reactions of hydrocarbons in electrical discharges. Chemical Reviews. Vol. 28, no. 1 (1941). p. 1-70
(30) Pruett, K.M. Chemical resistance guide to metals and alloys: a guide to chemical resistance of metals and alloys. Compass Publications, 1995. p. 122-133
(31) Pruett, K.M. Chemical resistance guide for plastics: a guide to chemical resistance of engineering thermoplastics, fluoroplastics, fibers and thermoset resins. Compass Publications, 2000. p. 170-181
(32) Propane. In: NIOSH pocket guide to chemical hazards. National Institute for Occupational Safety and Health, June 1997

Information on chemicals reviewed in the CHEMINFO database is drawn from a number of publicly available sources. A list of general references used to compile CHEMINFO records is available in the database Help.


Review/Preparation Date: 2005-02-18

Revision Indicators:
Vapour pressure at 50 deg C 2006-01-17
Relative density 2006-09-28



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