Chloroform

CAS number 67-66-3

Description

Chloroform (trichloromethane) is a colourless liquid with a pleasant, non irritating odour and a slightly sweet taste. It will burn only when it reaches very high temperatures.

Uses

Chloroform is primarily used in the production of refrigerants (e.g. chlorofluorocarbon (CFC)-22, fluorocarbon-22), in the production of plastics (especially vinyl chloride) and in the manufacture of other chemicals.

One of its most significant uses is in the production of monochlorodifluoromethane (CFC-22), a key component of polytetrafluoroethylene (Teflon) and other fluoropolymers. This reaction is carried out with hydrogen fluoride and a small amount of mixed antimony halides, resulting in the formation of chlorodifluoromethane, which is then converted to tetrafluoroethylene, the main precursor to Teflon.

Chloroform can be used as an extraction solvent for fats, oils, greases, rubber, waxes, gutta-percha, resins, lacquers, floor polishes, artificial silk manufacture, gums and adhesives. It is utilised as an industrial solvent in the extraction and purification of some antibiotics, alkaloids, vitamins and flavours. It is used as a solvent in organic chemistry, in photography and in making dyes, drugs and pesticides.

Other uses are as a dry cleaning agent to remove spots, as a fumigant and in fire extinguishers to lower the freezing temperature of carbon tetrachloride.

Chloroform is steadily being replaced by less toxic solvents and may no longer be used in some of these applications. In the past, chloroform was used as an inhaled anaesthetic during surgery, but it isn’t used that way today.

Chloroform may be released to the air from many sources related to its manufacture and use, as well as its formation in the chlorination of drinking water, wastewater, and swimming pools. Pulp and paper mills, hazardous waste sites, and sanitary landfills are also sources of air emissions.

People may be exposed to chloroform by breathing contaminated air or by eating food containing chloroform. Drinking or swimming water may also be a source of exposure to very small amounts of chloroform. Chloroform is a by-product of water chlorination and is therefore present in drinking water.

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.

Why it can be problematic for human and animal health

Exposure to chloroform can be by inhalation, dermal contact or ingestion.

Chloroform is shown in scientific literature as being associated with the following chronic health impacts:

Liver damage
Possible cancer causing – unknown in humans but cancer causing in animals – liver, kidney and thyroid.
Effects on blood and kidneys and central nervous system
Possible reproductive and developmental effects shown in animal studies, including reducing male sperm count
Repeated skin contact with chloroform can cause drying and cracking of the exposed skin areas

People with breathing problems such as asthma may be more sensitive to the effects of chloroform.

Acute exposure of humans to chloroform leads to dizziness and drowsiness. More severe exposures to chloroform may cause heart problems (arrythmia), 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.

Please note any adverse health effects that you may encounter in exposure to a chemical 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.