The chemical once in lava lamps, fire extinguishers and dry shampoo
For about 70 years carbon tetrachloride was sold as the safe cleaner, a non-flammable swap for gasoline. It filled fire extinguishers, weighted the wax in lava lamps and even went into dry shampoo. It is also one of the most powerful liver poisons known, which is why it largely vanished from everyday life.
The molecule is simple: one carbon atom surrounded by four chlorine atoms at the corners of a tetrahedron, the same shape as methane. That symmetry makes it non-polar, so it dissolves fats, oils and grease readily. The French chemist Henri Victor Regnault first made it around 1839 by adding chlorine to chloroform in sunlight, measuring its boiling point at 78 degrees Celsius. Hermann Kolbe found another route in 1843, and today most of it comes from methane.
Its uses were remarkably varied. Marketed as Katharin in the early 1890s, it cleaned clothes and, in the 1940s, typewriter keys. It was the first chlorinated solvent used in dry cleaning, until the 1950s, when corrosion of machinery and sickness among workers led to safer replacements. Stamp collectors dabbed it on the back of stamps to reveal hidden watermarks. Physicist Raymond Davis Jr. used a version made with heavy chlorine-37 in experiments to catch antineutrinos.
The hazards were serious. In a fire it can turn into poisonous phosgene, and deaths occurred when it was used in extinguishers. As a dry shampoo ingredient from 1903 into the 1930s, its fumes made several women faint in salons, and one 29-year-old woman died after a hair wash in 1909. It is toxic enough to the liver that researchers use it to test drugs designed to protect that organ, and alcohol makes its effects worse. The cancer agency IARC lists it as possibly carcinogenic to humans. In the 1860s doctors briefly tried it as an anaesthetic on at least 50 patients, but violent muscle spasms and heart problems ended the experiment.
It also damages the ozone layer and traps heat, lingering for about 85 years in the atmosphere. Production in the United States, Europe and Japan was about 720,000 tonnes in 1992, and by the 2010s annual American production and imports had dropped below 70,000 tonnes. Atmospheric levels have been falling since 1992.
Source: Carbon tetrachloride
