2,4,6-Trichlorophenol, also known as TCP, phenaclor, Dowicide 2S, Dowcide 2S, omal, is a chlorinated phenol that has been used as a fungicide, herbicide, insecticide, antiseptic,[3] defoliant, and glue preservative.

[4] It is a clear to yellowish crystalline solid with a strong, phenolic odor.

It decomposes on heating to produce toxic and corrosive fumes including hydrogen chloride and chlorine.

2,4,6-Trichlorophenol is produced industrially by the electrophilic chlorination of phenol:[5] In animal models, consumption of 2,4,6-trichlorophenol leads to an increased incidence of lymphomas, leukemia, and liver cancer.

[6][7] It is classified as Group B2 (probable human carcinogen) by the United States Environmental Protection Agency.