April 4, 2024

Two Final Tox Profiles Newly Available from ATSDR

Final toxicological profiles for the substance 1,1,1-trichloroethane and the group of human-made chemicals hexachlorocyclohexanes (HCH) are now available from the Agency for Toxic Substances and Disease Registry (ATSDR). 1,1,1-Trichloroethane previously had several industrial and residential uses, including as a solvent and as a component of household products like spot cleaners, glues, and aerosol sprays. In 2002, EPA banned its production for domestic use in the U.S. due to the substance’s effects on the ozone layer, but some production of 1,1,1-trichloroethane continues today. Exposure to the chemical can cause a variety of neurological and hepatic effects. Workers may encounter it in occupational settings where it is made or used, though the manufacture and use of 1,1,1-trichloroethane has “significantly decreased” in the U.S., according to ATSDR.

The new version of the final tox profile for HCH explains that HCH is a mixture of eight isomers, one of which (lindane) is an organochlorine insecticide that was used broadly in agriculture in the U.S. and around the world beginning in the 1940s. EPA began limiting the use of lindane for agricultural purposes in the 1970s due to concerns related to human health and eventually, in 2006, canceled the agency’s registrations for products containing lindane. Food and Drug Administration-regulated prescription products containing 1 percent lindane remain available as treatments for lice and scabies, and use of these products typically results in the highest exposures to lindane. Workers in facilities that use, package, or process lindane and people who live near sites contaminated with HCH may also have increased exposure. Studies of health effects in animals following exposure to HCH lead ATSDR to conclude that presumed health effects for humans include hepatic, neurological, developmental, and immune system problems.

Tox profiles are peer-reviewed evaluations of toxicological information on hazardous substances. A full list of toxic substances with published profiles is available on ATSDR website.