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.
At 400–500 °C, a free radical halogenation occurs, converting these precursors to progressively more chlorinated compounds:

CH4 + Cl2 → CH3Cl + HCl
CH3Cl + Cl2 → CH2Cl2 + HCl
CH2Cl2 + Cl2 → CHCl3 + HClChloroform undergoes further chlorination to yield carbon tetrachloride (CCl4):

CHCl3 + Cl2 → CCl4 + HClThe output of this process is a mixture of the four chloromethanes (chloromethane, dichloromethane, chloroform, and carbon tetrachloride), which can then be separated by distillation.Chloroform may also be produced on a small scale via the haloform reaction between acetone and sodium hypochlorite:
3 NaClO + (CH3)2CO → CHCl3 + 2 NaOH + CH3COONa

Deuterochloroform
Deuterated chloroform is an isotopologue of chloroform with a single deuterium atom. CDCl3 is a common solvent used in NMR spectroscopy. Deuterochloroform is produced by the haloform reaction, the reaction of acetone (or ethanol) with sodium hypochlorite or calcium hypochlorite. The haloform process is now obsolete for the production of ordinary chloroform. Deuterochloroform can be prepared by the reaction of sodium deuteroxide with chloral hydrate. Inadvertent formation of chloroform
The haloform reaction can also occur inadvertently in domestic settings. Bleaching with hypochlorite generates halogenated compounds in side reactions; chloroform is the main byproduct. Sodium hypochlorite solution (chlorine bleach) mixed with common household liquids such as acetone, methyl ethyl ketone, ethanol, or isopropyl alcohol can produce some chloroform, in addition to other compounds such as chloroacetone or dichloroacetone.