Chloroform: general information
Updated 6 August 2024
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Overview
Chloroform is a clear, colourless, volatile liquid with a characteristic sweet odour. It is non-flammable and emits toxic fumes on decomposition.
Uses of chloroform
Chloroform was mainly used in the production of refrigerant HCFC-22 (chlorodifluoromethane or hydrochlorofluorocarbon 22) for use in air conditioners or large supermarket freezers. These have been banned in new equipment since 2004, and are being phased out from existing machinery.
Chloroform is used in pesticide formulations, as a solvent and chemical intermediate in laboratories and industry, as a cleansing agent, in the production of dyes, in fire extinguishers and in the pharmaceutical and rubber industries. It is also used in the manufacture of fluorocarbon plastics, resins and propellants.
In the past, chloroform was extensively used to induce and maintain medical anaesthesia. Its use as an anaesthetic was discontinued due to the severe adverse health effects associated with its use.
How chloroform gets into the environment
Chloroform can exist naturally in the environment. It is also released into the environment from workplaces where it is manufactured.
Chloroform is indirectly produced when chlorine reacts with organic compounds. Therefore, a number of water disinfection processes including chlorination of drinking water, waste water and swimming pools contribute to the formation and release of chloroform into the environment. Disinfection processes at pulp and paper plants are also potential sources of chloroform.
Exposure to chloroform
People may be exposed to chloroform by breathing contaminated air or by eating food containing chloroform. Drinking water may also be a source of exposure to very small amounts of chloroform.
Workers involved in the production and use of chloroform and those working at sites where chloroform is indirectly produced (for example water treatment plants), may be exposed to higher levels of chloroform than the general population. However, safe limits are enforced to protect the employees; such levels are below those that are thought to cause harmful effects.
How exposure to chloroform could affect my health
The presence of chloroform in the environment does not always lead to exposure. In order for it to cause any adverse health effects, you must come into contact with it. You may be exposed by breathing, eating, or drinking the substance or by skin contact. Following exposure to any chemical, the adverse health effects that you may encounter depend on several factors, including the amount to which you are exposed (dose), the way you are exposed, the duration of exposure, the form of the chemical and if you were exposed to any other chemicals.
Inhalation of chloroform vapours may lead to symptoms such as shortness of breath and dryness of the mouth and throat. Ingestion of chloroform can cause a burning sensation in the mouth and throat, nausea and vomiting.
Chloroform can be absorbed into the body via ingestion or inhalation. Symptoms include excitement and nausea followed by dizziness and drowsiness. More severe exposures to chloroform may cause heart problems, fitting, unconsciousness and in some cases death. Delayed effects (up to 48 hours after the exposure) of acute toxic chloroform exposure are liver and kidney damage.
Skin contact with chloroform may lead to irritation and inflammation of the exposed area. Exposure of the eyes to chloroform vapour may cause a stinging sensation, and eye contact with liquid chloroform can cause immediate pain and inflammation.
Long-term exposure to chloroform can cause liver damage.
Chloroform and cancer
The International Agency for Research on Cancer has concluded that there is enough evidence in experimental animals, but not in humans that chloroform can cause cancer. Therefore, it has classified chloroform as possibly having the ability to cause cancer in humans.
Vulnerable people
People with breathing problems such as asthma may be more sensitive to the effects of chloroform.
Pregnancy and the unborn child
Available evidence does not indicate that exposure to chloroform during pregnancy will have a direct effect on the unborn child. However, if the exposure to chloroform causes the mother to become unwell this may affect the health of the unborn child.
Children
Children will be affected by chloroform in the same way as adults.
What to do if you are exposed to chloroform
It is very unlikely that the general population will be exposed to a level of chloroform high enough to cause adverse health effects. However, if you have any health concerns regarding exposure to chloroform seek guidance from your GP or contact NHS 111.
Additional sources of information
- UKTIS best use of medicines in pregnancy (bumps)
- NHS.UK has information about poisoning