Chloroethane, also called ethyl chloride, is a colorless gas at room temperature and pressure, with a characteristically sharp odor. People can smell chloroethane in the air at levels above 4 parts chloroethane in a million parts of air by volume (ppm). It can be smelled in water at levels above 0.02 parts chloroethane in a million parts of water (ppm). In pressurized containers, chloroethane exists as a liquid. However, the liquid evaporates quickly when exposed to air. It catches fire easily and is very dangerous when exposed to heat or flame. Chloroethane does not occur naturally in the environment. It is present in the environment as a result of human activity.
In the past, the largest single use for chloroethane was for the production of tetraethyl lead, which is a gasoline additive. However, production of chloroethane has decreased dramatically as a result of stricter government regulations controlling lead in gasoline. Other applications include use in the production of ethyl cellulose, dyes, medicinal drugs, and other commercial chemicals, and use as a solvent and refrigerant. It is used to numb skin prior to medical procedures such as ear piercing and skin biopsies, and it is used in the treatment of sports injuries.
Pathways for chloroethane in the environment
Most of the chloroethane released to the environment ends up as a gas in the atmosphere, while much smaller amounts enter groundwater as a result of passage through soil. Once in the atmosphere, chloroethane breaks down fairly rapidly by reaction with substances in the air. It takes about 40 days for half of any given amount of chloroethane that is released to the atmosphere to disappear. In groundwater, chloroethane changes slowly to ethanol and a chloride salt as a result of reaction with water. In addition, some types of bacteria present in the water may break down chloroethane to smaller compounds. However, not enough is known about chloroethane to be sure if this occurs or how long it may remain in groundwater.
Exposure to chloroethane
Humans can be exposed to chloroethane from environmental, occupational, and consumer sources. During the mid-to-late 1970s and the early 1980s, chloroethane was detected in samples of outdoor air. Air samples collected in urban and suburban areas contained chloroethane at an average level of 41–140 parts of chloroethane in a trillion parts of air (ppt; 1 ppt is 1,000,000 times less than 1 ppm). Rural air samples contained less than 5 ppt. Current levels of chloroethane in the air are expected to be even lower than levels found in the past because of the sharp decrease in chloroethane production in the United States and the decrease in chloroethane release. Occurrences of chloroethane in air can be attributed to releases from factories that manufacture or use chloroethane; evaporation from some landfills, solvents, refrigerants, and anesthetics; and releases in fumes from the burning of plastics and other materials found in trash. Based on the limited amount of information available on the occurrence of chloroethane in drinking water, it can be concluded that extremely low levels of chloroethane may occur in some drinking water supplies as a result of formation during chlorination, contamination of rivers and lakes used as drinking water supplies, or seepage into groundwater resulting from storage of chemical wastes or disposal at waste sites. However, there is not enough information available to indicate what levels of chloroethane occur in drinking water under these circumstances. No data were located that indicate that chloroethane is found in food.
Exposure may also result from contact with various consumer products including some solvents, paints, and refrigerants. People may be exposed to chloroethane through skin contact as the result of its use as an agent to numb skin before ear piercing, before skin biopsy, as a treatment for sports injury, and for other medical reasons. Occupational exposure may result from inhalation or skin contact. Workers who may be exposed to chloroethane include physicians, nurses, and other medical workers, automobile mechanics, office machine mechanics, household appliance and accessory installers, assemblers, professional painters, heavy-equipment mechanics, diesel mechanics, plumbers, and pipe fitters. According to a National Institute for Occupational Safety and Health (NIOSH) survey conducted between 1981 and 1983, an estimated 49,212 workers in the United States were exposed to chloroethane in the workplace. More recent data are not available to determine how many workers might be exposed to chloroethane per year in the United States.
Pathways for chloroethane in the body
Chloroethane can enter the body when a person breathes air containing chloroethane vapor. Chloroethane may also enter the body through the skin, although most of it quickly evaporates from the skin's surface. When a person drinks water containing chloroethane, it enters the body through the digestive tract. After chloroethane enters the body, it may leave the body through the lungs. Some chloroethane may also be changed to acetate, which is normally found in the body. Other chemicals formed from chloroethane leave the body in the urine.
People who happen to be near hazardous waste sites containing chloroethane are most likely to be exposed to the compound by breathing potentially contaminated air. People may also be exposed to chloroethane by drinking potentially contaminated water.
Health effects of chloroethane
To protect the public from the harmful effects of toxic chemicals and to find ways to treat people who have been harmed, scientists use many tests.
You should know that one way to learn whether a chemical will harm people is to determine how the body absorbs, uses, and releases the chemical. For some chemicals, animal testing may be necessary. Animal testing may also help identify such health effects as cancer or birth defects. Without laboratory animals, scientists would lose a basic method for getting information needed to make wise decisions that protect public health. Scientists have the responsibility to treat research animals with care and compassion. Scientists must comply with strict animal care guidelines because laws today protect the welfare of research animals.
Additionally, there are vigorous national and international efforts to develop alternatives to animal testing. The efforts focus on both in vitro and in silico approaches and methods. For example, the National Toxicology Program (NTP) at the National Institute of Environmental Health Sciences (NIEHS) created the NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) in 1998. The role of NICEATM is to serve the needs of high quality, credible science by facilitating development and validation—and regulatory and public acceptance—of innovative, revised test methods that reduce, refine, and replace the use of animals in testing while strengthening protection of human health, animal health and welfare, and the environment. In Europe, similar efforts at developing alternatives to animal based testing are taking place under the aegis of the European Centre for the Validation of Alternative Methods (ECVAM).
Brief exposure to high levels of chloroethane vapor can produce temporary feelings of drunkenness, and at still higher levels, lack of muscle coordination and unconsciousness. Adults have felt dizzy and have suffered decreased reaction times as a result of inhaling chloroethane. They have also experienced stomach cramps, nausea, vomiting, and eye irritation after breathing high concentrations of chloroethane for a short time.
Workers who breathed chloroethane vapors for 1.5 to 3 years (levels of chloroethane unknown) had significantly decreased defensive responses against illness. Inhalant abusers who intentionally breathe chloroethane vapors at much higher concentrations than those found in any work environment or near any hazardous waste site have experienced these neurological effects. Long term abuse of high chloroethane concentrations causes the most adverse effects of chloroethane exposure, namely, those to the nervous system. In the worst recorded cases of chloroethane abuse by sniffing, the abusers have had severe symptoms including jerking eye movements, an inability to control muscles in voluntary movements, difficulty in speaking clearly, an inability to perform finger tapping exercises, sluggish lower limb reflexes, seizures, difficulties in walking, disorientation, short-term memory loss, and hallucinations affecting their sight and hearing. In one case, damage to motor and sensory nerves occurred.
Human patients have died after breathing chloroethane concentrations high enough to induce anesthesia. Dogs have suffered irregular heart rhythms, followed by death, when given anesthetic doses of chloroethane. Due to the risk of accidental death, chloroethane is no longer medically used as a general anesthetic during major surgery. Chloroethane can, however, be applied to the skin in the form of chloroethane spray as a numbing agent prior to minor surgery. If this spray is applied for too long, frostbite can result. Some adults have had allergic reactions to the chloroethane spray while others experienced mild pain after being sprayed for 10 seconds.
Studies have shown that chloroethane can enhance the effects of alcohol in rats. It is unknown if similar interactions between chloroethane and alcohol occur in humans.
It is not known whether chloroethane produces cancer in humans. However, long-term exposure to high levels of chloroethane vapor has been shown to produce cancer in mice. There have been no animal or human studies involving the ability of chloroethane to cause cancer when either eaten or applied to the skin. The International Agency for Research on Cancer (IARC) has reviewed the information available concerning the ability of chloroethane to cause cancer. They concluded that chloroethane is not classifiable as to its carcinogenicity in humans.
Health effects in children
This section discusses potential health effects from exposures during the period from conception to maturity at 18 years of age in humans. Potential effects on children resulting from exposures of the parents are also considered.
There are no known unique exposure pathways by which children may be exposed to chloroethane.
In children, there have been few recorded reports of exposures to chloroethane or adverse health effects resulting from this exposure. Brief inhalation exposure of children to very high concentrations of chloroethane has resulted in stimulation of certain nerves followed by a decrease in heart rate. One teenager died from lung paralysis during general anesthesia with chloroethane. In addition to these health effects seen specifically in children, the observed adverse effects of chloroethane exposure in adults are also expected in children. It is unknown whether children differ from adults in their susceptibility to health effects from chloroethane exposure.
We do not know whether chloroethane exposure can affect development in humans. There is not enough information to know whether chloroethane affects development in animals. Only one developmental study has been done in animals. This study with mice showed that exposure to high levels of chloroethane during pregnancy delayed bone development in the offspring.
We do not know whether chloroethane or its breakdown products within the body can reach and cross the mother's placenta into her developing baby. One study has shown that chloroethane can be found in mother's milk, but we do not know if the mothers were exposed to the compound by breathing it, eating it, or having it sprayed on their skin.
Reducing risk of exposure to chloroethane
If your doctor finds that you have been exposed to significant amounts of chloroethane, ask if children may also be exposed. When necessary your doctor may need to ask your state Department of Public Health to investigate.
Little information exists concerning the concentrations of chloroethane that might be present in drinking water. However, past data indicate that chloroethane is not a frequent contaminant in drinking water, and therefore the risk to families from drinking water containing chloroethane is low.
Chloroethane is found in common household products such as paints, solvents, air fresheners, and deodorant sprays. Inhaling or ingesting toxic amounts of chloroethane from these products is possible. Therefore, household products such as these should be stored out of reach of young children to prevent accidental poisonings. Always store household chemicals in their original labeled containers; never store household chemicals in containers children would find attractive to eat or drink from, such as old soda bottles. Keep your Poison Control Center's number by the phone.
Sometimes older children sniff household chemicals in an attempt to get high. Chloroethane is sold in drug paraphernalia shops as Ethyl Gaz, Ethyl Four Star, Black Jac, and Maximum Impact. Your children may be exposed to chloroethane by inhaling products containing it and are putting their health at serious risk if they do so. Talk with your children about the dangers of sniffing chemicals.
When household products that contain chloroethane are used properly and are not abused, the concentrations of chloroethane within them are not high enough to pose a risk of significant exposure to children.
The tendency of chloroethane to evaporate upon contact with air makes it highly unlikely that the compound could be taken home on the parents' work clothes.
Medical tests for exposure to chloroethane
Although there are complex analytical tests that chemists use to measure chloroethane in the blood, milk, or urine, there are no commonly used medical tests available to determine whether or not a person has been exposed to chloroethane. A breath test to determine exposure may be possible but is not commonly used.
Disclaimer: This article is taken wholly from, or contains information that was originally published by, the Agency for Toxic Substances and Disease Registry. Topic editors and authors for the Encyclopedia of Earth may have edited its content or added new information. The use of information from the Agency for Toxic Substances and Disease Registry should not be construed as support for or endorsement by that organization for any new information added by EoE personnel, or for any editing of the original content.