Sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES)

Sodium lauryl sulfate is a skin irritant and Environment Canada's preliminary categorization of this chemical indicates that it may be toxic to the environment. Sodium laureth sulfate is the "ethoxylated" form of this chemical, which is less harsh. However, the process of ethoxylation can leave behind traces of 1,4-dioxane, a possible human carcinogen that is persistent in the environment (see also DEA, MEA, TEA).

Found in: dish soap, liquid laundry detergents, cleaning towelettes, and toilet bowl cleaners (as well as sudsy cosmetics).