Haloacetic acids

Haloacetic acids or HAAs are carboxylic acids in which one or more halogen atoms take the place of hydrogen atoms in the methyl group of acetic acid. Those acids have a general chemical formula X¹X²X³C−CO₂H, where X is hydrogen or halogen, and at least one X is a halogen. In a monohaloacetic acid (XCH₂−CO₂H), a single halogen replaces a hydrogen atom: for example, in bromoacetic acid (BrCH₂−CO₂H). Further substitution of hydrogen atoms with halogens can occur, as in dichloroacetic acid (Cl₂CH−CO₂H) and trichloroacetic acid (Cl₃C−CO₂H).

Haloacetic acids are a common contaminant in treated drinking water, particularly water subjected to chlorination.