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Readers of a certain age can remember when “carbon tet� was the go-to household solvent that easily removed organic residues such as adhesives and oils from almost any surface. It was also a widely used dry-cleaning solvent, refrigerant, and fire suppressant.

During the 1970s and â€�80s, however, toxicologists discovered that inhalation of or skin contact with carbon tetrachloride (CCl₄) can damage many organs, including the liver, kidneys, and central nervous system (see hazard table). CCl₄ is also a “greenhouse gasâ€� that, according to the 1995 Montreal Protocol, depletes ozone in the Earth’s stratosphere. Consequently, production and use have been significantly reduced.

In its heyday, CCl₄ was produced by chlorinating C₁ compounds such as chloroform, carbon disulfide, and, in later years, methane. What little is available today is a coproduct from the manufacture of chloroform and dichloromethane; however, US production is still .

The CCl₄ currently produced is used as a feedstock for ozone-safe refrigerants and in some minor agricultural and industrial processes. In a recent draft risk assessment of CCl₄ standards under the Toxic Substances Control Act, the US Environmental Protection Agency reports that the compound is safe to use in manufacturing plants . The assessment is scheduled to be finalized by June.