Fact sheet: Pentachlorophenol

From: Public Services and Procurement Canada

Discover a list of a contaminant's important chemical properties, how it will react in the environment, main sources of contamination related, and a brief overview of health and safety issues.

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General information

CAS number


Molecular formula


Formula weight

266.3 g/mol


Phenolic compounds

Properties (at room temperature where applicable)

Compound properties list
Melting/boiling point191 °CSolid
Relative density1.98 g/cm3Sinks in water
Vapour pressure5 x 10 -5 mm HgVery low volatility
Vapour density0N/A
Solubility in water3,000 mg/LModerately soluble
Henry's law constant5 x 10-7atm·m3/molSlow volatilization when dissolved
log Koc (Depending on soil or sediment characteristics)2.5 - 4.0*Strong adsorption to organic matter

Environmental behaviour

At 20 0C, pentachlorophenol is a solid with very low volatility and moderate solubility. Once it is dissolved, it volatilizes slowly and adsorbs strongly to organic matter. When present in the soil, it volatilizes very slowly. Once dissolved, pentachlorophenol can reach the water table or migrate into a waterway, where it will be diluted before volatilizing slowly. Fragments of pentachlorophenol can also be carried into a watercourse where they will deposit at the bottom of dissolve. Once the source is gone, the adsorbed phase will take a while to disappear, being released in its gaseous or dissolved (primarily) forms. The resulting dissolved plume will be moderate in size while the gaseous plume will be insignificant.

Health and safety

Pentachlorophenol should be handled with care as it is toxic.

Principal resources

Since 1986, pentachlorophenol used in Canada has been obtained from U.S. and European manufacturers. Commercial pentachlorophenol, which is more frequently used as a wood preservative, contains approximately 4% tetrachlorophenols and 0.1% trichlorophenols. The domestic use of pentachlorophenol, in 1990, was restricted to exterior wood preservatives containing 3.3% to 5% pentachlorophenol in petroleum distillates and applied as clear finishes, water repellents, or stains. In Canada, all indoor and spray applications of chlorophenol were discontinued in 1981.

The amount of pentachlorophenol used for agricultural purposes was low when compared to the wood treatment industry. Pentachlorophenol was used primarily to prevent wood decay in farm buildings, fences, and storage facilities. Pentachlorophenol and its sodium salt have also been used as herbicides and desiccants for forage seed crops, herbicides for nonfood vegetation control, biocides for post-harvest washing of fruit and as insecticides for use in beehives, seed plots and greenhouses.

The biocidal properties of pentachlorophenol have made it useful as an anti-algal and anti-fungal agent in industrial boilers, cooling systems, latex paints and paper making.


Agency for Toxic Substances and Disease Registry (ATSDR). 1999. Toxicological profile for Chlorophenols. U.S. Department of Health and Human Services, Public Health Service, Georgia, U.S.A. (Viewed December 2013)

Canadian Council of Ministers of the Environment. 1999. Canadian water quality guidelines for the protection of aquatic life: Pentachlorophenols. In: Canadian environmental quality guidelines, 1999. Canadian Council of Ministers of the Environment, Manitoba, Canada. (Viewed December 2013)

Montgomery, John H. 2007. Groundwater Chemicals, Desk Reference, Fourth Edition, CRC Press, Taylor and Francis Group, Florida, U.S.A.