Pure pentachlorophenol is a white, crystalline, aromatic compound. Impure pentachlorophenol is dark gray to brown and exists as dust, beads, or flakes. It may also be referred to as PCP or ‘penta’. There are numerous other synonyms and product names; see HSDB for more information.
Combined exposures to polychlorophenols or their sodium salts have been classified by IARC as Group 2B, possibly carcinogenic to humans. There is sufficient animal evidence for the carcinogenicity of pentachlorophenol in particular; it caused adrenal tumours in mice. In humans, there are suggested links to non-Hodgkin lymphoma (NHL) and soft tissue sarcomas in those occupationally exposed. In particular, a recent Canadian study found strong dose-response relationships between pentachlorophenol exposure and NHL, multiple myeloma, and kidney cancer.
Additionally, acute exposure to pentachlorophenol can cause fever and respiratory distress. Damage to the liver and immune system as well as reproductive and developmental effects have been observed in humans exposed to high levels of pentachlorophenol over long periods of time. Impurities in the PCP, however, such as dioxins and furans at parts per million levels, may also contribute to these effects.
stel = short term exposure limit (15 min. maximum)
Canadian Environmental Guidelines
Canadian Drinking Water Guidelines
0.6 [AO < 0.03]
AO = aesthetic objective
Pentachlorophenol was not included in other Canadian government environmental guidelines reviewed.[22-24]
DSL – high priority substance with intermediate potential for exposure
Agreement Respecting the Great Lakes Basin Ecosystem
Tier II Substance
Pentachlorophenol was not included in other Canadian government chemical listings reviewed.[29,30] Although pentachlorophenol is persistent and inherently toxic to humans and other organisms, it is not included in CEPA because it falls under the Pest Control Products Act. Its management is the responsibility of the Pesticides Management Regulatory Agency.
Pentachlorophenol and its sodium salt are primarily used as a fungicide for industrial wood preservation. It is used for utility poles, railroad ties, foundation pilings, timbers in highway construction, construction timbers and poles, bridge timbers & ties, and fence posts.
PCP can be applied to wood via pressure-treating or by thermal impregnation, where PCP is applied by spraying, dipping, brushing or soaking the wood.
Pentachlorophenol was registered for public use by the United States EPA until 1984. Since then it has been a restricted pesticide in the US, available only to certified applicators. Pentachlorophenol was formerly used in agriculture as an herbicide, defoliant, bactericide and molluscicide.
PCP may also have limited use in leather tanning, where it is used as a biocide. Current information on its use in this industry was not located.
Canadian Production and Trade
According to a 1995 report, pentachlorophenol has not been produced in Canada since the early 1980s.
In 2000, between 100 and 1,000 tonnes of pentachlorophenol (concentration >1%) were imported into Canada for use as a wood preservative.
Production and Trade
2,200 t in 1981 (last year produced)
Import: Mainly from Mexico, US
1,997 t of ‘pentachlorophenol ISO’
t = tonne
Occupational exposure occurs via dermal contact with the compound or with treated wood products, or via inhalation of contaminated workplace air (i.e. during production or use of pentachlorophenol).[2,3] Dermal contact is the most important route of exposure; one study found that it accounted for 95% of total worker exposure in sawmills.
The highest potential for occupational exposure in Canada is currently in the wood manufacture and preservation industry. Exposure can occur during application and handling of treated products.[2,28]
The general population is most likely to be exposed to pentachlorophenol in the vicinity of hazardous waste sites. This can occur via inhalation, ingestion of contaminated groundwater or food, or dermal contact with soils. In older homes that contain pentachlorophenol-treated wood, occupants can be exposed to low levels of pentachlorophenol in indoor air, or via dermal exposure from touching treated wood.
People who work or live near a wood treatment facility or where production of utility poles, railroad ties, or wharf pilings occurs may be exposed to pentachlorophenol.
Pentachlorphenol was not reportable to the National Pollutant Release Inventory or the US Household Products Database.