DCA has been shown to occur in nature in at least one seaweed, "Asparagopsis taxiformis". It is a trace product of the chlorination of drinking water and is produced by the metabolism of various chlorine-containing drugs or chemicals. DCA is typically prepared by the reduction of trichloroacetic acid (TCA). DCA is prepared from chloral hydrate also by the reaction with calcium carbonate and sodium cyanide in water followed by acidifying with hydrochloric acid. It can be also made by passing acetylene through solutions of hypochlorous acid.