California's OEHHA Intent to List Pentachlorophenol (October 2015)California’s Office of Environmental Health Hazard Assessment (OEHHA) intends to add “pentachlorophenol and by-products of its synthesis (complex mixture)” to the list of chemicals known to cause cancer under the Safe Drinking Water and Toxic Enforcement Act of 1986. This action is being proposed under the authoritative bodies listing mechanism.
The commercially available mixture is a restricted-use pesticide and registered as a heavy-duty wood preservative for structures such as utility poles, cross arms and construction material. Indoor uses were cancelled in 1984 and non-wood preservative uses were cancelled and restricted in 1987.
CAS No. &
|Toxicological Endpoints||Listing Mechanism|
|Pentachlorophenola and by‑products of its synthesisb (complex mixture)||
Pentachlorophenol (87-86-5), and Pentachlorophenol, sodium salt (131-52-2)
|Cancer||The commercially available complex mixture of pentachlorophenol and by-products of its synthesis is a restricted-use pesticide and registered as a heavy-duty wood preservative for utility poles, cross arms, pilings, fence posts, and construction. It is also used as a competitive inhibitor of sulfotransferase in the laboratory. The complex mixture was used in the past as a biocide in ropes, paints, adhesives, leather, canvas, insulation, and brick walls. Indoor uses were cancelled in 1984. Non-wood preservative uses were cancelled and restricted in 1987.|
a Pentachlorophenol is currently listed as known to the state to cause cancer under Proposition 65. This listing includes the byproducts of pentachlorophenol synthesis, which are found in varying amounts in pentachlorophenol and the sodium salt formulations.
bThe commonly found by-products of pentachlorophenol synthesis include polychlorinated phenols (trichlorophenols and tetrachlorophenols), hexachlorobenzene, polychlorinated dibenzofurans (hexachlorodibenzofurans, heptachlorodibenzofurans, and octachlorodibenzofuran), polychlorinated dibenzo-p-dioxins (hexachlorodibenzo-p-dioxins, heptachlorodibenzo-p-dioxins, and octachlorodibenzo-p-dioxin), whereas 2,3,7,8-tetrachlorodibenzo-p-dioxin is a less commonly found by-product. Among them, 2,4,6-trichlorophenol, hexachlorobenzene, hexachlorodibenzodioxin, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans are listed as known to the state to cause cancer under Proposition 65.
c NTP = National Toxicology Program
For more information and a complete list of all major changes see: http://www.oehha.ca.gov/prop65/CRNR_notices/admin_listing/intent_to_list/NOIL103015pentachlrophenol.html