California lists pentachlorophenol complex mixture under Prop 65

California’s Office of Environmental Health Hazard Assessment (OEHHA) has listed pentachlorophenol and by-products of its synthesis (complex mixture) as a carcinogen under Proposition 65. The substance was added via the authoritative bodies listing mechanism. This was based on the report by the 2014 National Toxicology Program (NTP), published in the thirteenth edition of the Report on Carcinogens (RoC). In comments submitted to the agency, the pentachlorophenol task force said the listing would duplicate an existing one. The substance has been listed as a carcinogen under Prop 65 since 1990. But the agency disagreed, saying this is for a complex mixture of chemicals that co-occur with pentachlorophenol as a result of formation during its synthesis. And while some of the commonly found by-products are named individually under Prop 65, others are not, such as five trichlorophenol isomers and three tetrachlorophenol isomers, said the agency. The complex mixture is used as a preservative in heavy-duty wood, in such applications as construction, utility poles and fence posts. Non-wood biocidal uses have been restricted since 1987. The listing took effect on 21 October. Further information is available at: Listing notice

Chemical Watch, 25 October 2016 ; ;