Research published in the British medical journal The Lancet has newly identified six neurotoxins: manganese, fluoride, chlorpyrifos, dichlorodiphenyltrichloroethane (DDT), tetrachloroethylene (perchloroethylene or PERC) and polybrominated diphenyl ethers (PBDE).

Manganese exposure is found in welding and high-octane gas fumes, among other sources; fluoride is used in many municipal water supplies, glass etching and chrome cleaners. Chlorpyrifos is an organophosphate contained in many pesticides, including Dursban and Lorsban. While DDT has been banned from insecticides within the U.S., it is still contained in other agents, including petroleum distillates. DDT is also still used in some areas to spray for mosquitoes. PERC has often been used in dry cleaning and for degreasing metals. PBDEs appear as flame retardants and to make electronics, household goods, building materials, polyurethane foams, plastics and more.

The same researchers previously identified lead, methylmercury, polychlorinated biphenyls, arsenic and toluene as neurotoxins. The neurotoxin label means they affect the nervous system and can cause neurodevelopmental conditions such as autism, attention deficit disorders, dyslexia and others.