Chloroform, or trichloromethane, is an organic compound with formula CHCl3 and is a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to PTFE. It is also a precursor to various refrigerants. It is one of the four chloromethanes and a trihalomethane. It is a powerful anesthetic, euphoriant, anxiolytic, and sedative when inhaled or ingested. Structure
The molecule adopts a tetrahedral molecular geometry with C3v symmetry. Natural occurrence
The total global flux of chloroform through the environment is approximately 660000 tonnes per year, and about 90% of emissions are natural in origin. Many kinds of seaweed produce chloroform, and fungi are believed to produce chloroform in soil. Abiotic processes are also believed to contribute to natural chloroform productions in soils although the mechanism is still unclear.Chloroform volatilizes readily from soil and surface water and undergoes degradation in air to produce phosgene, dichloromethane, formyl chloride, carbon monoxide, carbon dioxide, and hydrogen chloride. Its half-life in air ranges from 55 to 620 days. Biodegradation in water and soil is slow. Chloroform does not significantly bioaccumulate in aquatic organisms. History
Chloroform was synthesized independently by several investigators circa 1831:

Moldenhawer, a German pharmacist from Frankfurt an der Oder, appears to have produced chloroform in 1830 by mixing chlorinated lime with ethanol; he mistook it for Chloräther (chloric ether, 1,2-dichloroethane), however.
losing consciousness instantaneously, using chloroform. Safety
Exposure
Chloroform is known to form as a by-product of water chlorination along with a range of other disinfection by-products and as such is commonly present in municipal tap water and swimming pools. Reported ranges vary considerably but are generally below the current health standard for total trihalomethanes of 100μg/L. Nonetheless, the presence of chloroform in drinking water at any concentration is considered controversial by some.Historically, chloroform exposure may well have been higher due to its common use as an anesthetic, as an ingredient in cough syrups, and as a constituent of tobacco smoke where DDT had previously been used as a fumigant. Pharmacology
It is well absorbed, metabolized, and eliminated rapidly by mammals after oral, inhalation, or dermal exposure. Accidental splashing into the eyes has caused irritation. Prolonged dermal exposure can result in the development of sores as a result of defatting. Elimination is primarily through the lungs in the form of chloroform and carbon dioxide; less than 1% is excreted in the urine.Chloroform is metabolized in the liver by the cytochrome P-450 enzymes, by oxidation to chloromethanol and by reduction to the dichloromethyl free radical. Other metabolites of chloroform include hydrochloric acid and digluathionyl dithiocarbonate, with carbon dioxide as the predominant end product of metabolism.Like most other general anesthetics and sedative-hypnotic drugs, chloroform is a positive allosteric modulator for the GABAA receptor. Chloroform causes depression of the central nervous system (CNS), ultimately producing deep coma and respiratory center depression. When ingested, chloroform caused symptoms similar to those seen following inhalation.