Before revision: Triclosan Reports have suggested triclosan, an active ingredient in many kinds of toothpastes, can combine with chlorine in tap water to form chloroform , which the United States Environmental Protection Agency classifies as a probable human carcinogen .
After revision: Triclosan Reports have suggested triclosan, an active ingredient in many kinds of toothpastes, can combine with chlorine in tap water to form chloroform .