Dichloromethane or methylene chloride is a chemical compound that appears as a colorless and volatile liquid at room temperature, emitting a relatively strong sweetish odor that may cause discomfort to some individuals. Its smell becomes noticeable at concentrations as low as 200–300 ppm.

Perchloroethylene, also known as tetrachloroethylene or PCE, is a solvent. This volatile organic compound is primarily used for dry cleaning fabrics and degreasing metals. It is listed in a table of occupational diseases due to its health effects.