Ongoing health problems among timber workers exposed to industry chemical PCP are to be investigated by the Centre for Public Health Research and led by Professor Neil Pearce.
The project, funded by the Ministry of Health, aims to ascertain whether timber workers exposed to the PCPs (pentachlorophenols) are dying earlier, getting cancers more often and suffering more chronic health problems, including fatigue, nausea and neuropsychological dysfunction.
Professor Pearce says the study addresses concerns expressed by former timber workers in the past decade about a range of chronic health problems they have experienced.
“These workers were exposed to PCPs through its use as an anti-sapstain fungicide in sawmills. Because of uncertainty over whether these health problems could be attributed to past PCP exposure, the Government has made funding available to commission research aimed at clarifying the issue,” he says.
Administered by the Health Research Council, the $520,000 study will compare timber workers’ death rates with national rates, and estimate the size of any risks attributable to PCPs. It will also involve a survey of current health problems in a random sample of former timber workers. The project advisory committee includes representatives of the Forest Industries Council, the unions representing former timber workers, Sawmill Workers Against Poisons (SWAP), the Ministry of Health, the Ministry for the Environment, ERMA, and OSH.
Serum samples will be taken from a random sample of former timber workers to validate exposure. Workers involved in wood treatment processes or in handling treated timber are known to have significant exposure to PCPs, which have contained contaminants and by-products including various types of dioxin. Jobs with potential for heavy exposure include handling of sludge formed in the bottom of dip tanks and any process involving the heating of PCP including burning treated wood or welding structures contaminated with PCP.
From the 1950s through to the late 1980s PCP was widely used in the New Zealand timber industry, and almost all freshly sawn timber treated to prevent sapstain fungi. The Department of Conservation estimates almost 600 sites in New Zealand are contaminated.
The organic chemical can be released into the atmosphere from treated wood and transported to surface water and soils. It is also released into the atmosphere from factory waste disposal, entering the soil as a result of spills, disposal at hazardous waste sites and its use as a pesticide. The compound can be present in fish or other food species and its levels are monitored by the USA Food and Drug Administration.
People are exposed to PCPs through contaminated drinking water, the inhalation of contaminated air and through the handling of treated timber, textiles, leather and paper products. PCP is completely and rapidly absorbed by the digestive tract where it enters the bloodstream, and accumulates in highest concentrations in the liver, kidneys and brain.
Professor Pearce was part of a team to undertake a preliminary study of the effects of occupational pentachlorophenol exposure for the Wellington Medical Research Foundation in 1998. He says the current project work fits well with the increasing number of other occupational health projects underway at the Centre.
These include: research on occupational causes of bladder cancer, leukaemia, non-Hodgkin’s lymphoma and nasopharyngeal cancer; studies of cancer in workers exposed to dioxin pesticide production or through work in pulp and paper mills; the work on occupational health in Mäori being carried out by Professor Chris Cunningham at Te Pumanawa Hauora; research on shiftwork and fatigue by Professor Philippa Gander at the Sleep/Wake Research Centre.