Pentachlorobenzene (PeCB)

Pentachlorobenzene (PeCB) was previously used for various purposes:

  • to reduce the viscosity of PCB products employed for heat transfer,
  • in dyestuff carriers,
  • as a fungicide,
  • in a flame retardant; and
  • as a chemical intermediate such as the production of quintozene (a soil fungicide).

PeCB is also produced unintentionally during combustion in thermal and industrial processes. It appears as an impurity in products such as solvents or pesticides.

PeCB may be emitted to the environment indirectly:

  • as a result of waste incineration and barrel burning of household waste;
  • in waste streams from pulp and paper mills, iron and steel mills, and petroleum refineries; and
  • in activated sludge from waste water treatment facilities.

Adverse effects

PeCB is classified within the EU as "Harmful if swallowed" and "Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment.

Suckling pups from mothers fed a dose of 12.5 mg/kg body weight developed tremors 4 - 14 days after birth. At a maternal dose of 6.3 mg/kg body weight this effect did not occur in pups. In another study, pregnant female rats were administered PeCB at levels of 50, 100 and 200 mg/kg body weight daily on day 6 through 15 of gestation. The number of live foetuses was not affected; however, the mean foetal weight was decreased in the highest dose group (Sloof et al., 1991).

Based on the data available, marine and freshwater organisms do not seem to differ significantly in sensitivity to PeCB.

Based upon acute and subchronic animal tests, PeCB is probably moderately toxic to humans. Based on experiments with aquatic species, PeCB is toxic for a range of aquatic organisms.

More information



Adapted from the Proposal for listing PeCB in the Stockholm Convention (Word file)

Hatfield Consultants The World Bank funded by the Canadian POPs Trust Fund through the      
Canadian International Development Agency
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