Department publishes study on dioxin exposure among timber workers

Former and current timber workers with historical exposure to a toxic timber treatment known as pentachlorophenol (PCP) are advised to talk to their doctor about any health concerns, the Department of Labour said today.

The Department today released research on health outcomes for timber workers exposed to PCP, that was used in sawmills until 1988. PCP is a hazardous substance in its own right, and was also contaminated with types of dioxin. The research, by Massey University’s Centre for Public Health Research, found:

Most sawmill workers had relatively low exposure to PCP and had mortality (death) rates similar to national rates.
Indications of a slightly higher risk of cancers in timber workers exposed to PCP, although the result was not statistically significant because the sample size was too small.
About 10% of sawmill workers in the study group had high or long-term exposure to PCP, and this group had relatively high levels of dioxin in their blood.
A link between high exposure to PCP and a range of health problems including unexplained fevers, recurrent nausea and diarrhoea, heart palpitations, unexplained sweating, reduced libido and frequent mood changes [that confirms previous New Zealand studies].
A link between high exposure and non-cancerous respiratory disease. This association has not been shown in other PCP research.
Timber workers who were exposed to PCP and are concerned about their health should talk to their GP about any treatment or health monitoring that may be required, says Department of Labour Deputy Secretary Workplace Andrew Annakin.

They should also see their GP for help making an ACC claim, Mr Annakin says. “Anyone who believes their health has been affected by exposure to PCP can make an ACC claim.”

ACC already considers claims for PCP poisoning from current and former timber workers on a case by case basis, and has accepted 59 of the 147 claims made since 1997. It accepts cancers as part of a PCP claim where evidence links the cancer type to PCP or dioxins, and it is shown that there has been exposure at a level that may have contributed to the cancer.

The Department of Labour is working to publicise the results of the Massey University research with relevant groups, including current and former timber workers, health providers and other relevant government agencies.

Massey University’s research, published in a report Health outcomes in former New Zealand timber workers exposed to pentachlorophenol, was funded by the Department of Labour and managed by the Health Research Council of New Zealand.

The research is the largest and most comprehensive study of health outcomes for PCP-exposed timber workers done in New Zealand, Mr Annakin says. “It provides important information for health providers, government agencies, individual timber workers and others who are dealing with the consequences of these historical exposures to PCP.”

The full report is available at www.dol.govt.nz .

Editor’s Note:

Pentachlorophenol (PCP) was applied to freshly sawn timber in New Zealand sawmills between the 1950s and 1988 to prevent sap-stain caused by fungal growth on the timber.

PCP belongs to a group of chemicals know as organochlorines. PCP solutions used in New Zealand contained high levels of hexa-, hepta-, and octa-chlorinated dioxins. These dioxins are toxic, but considered less so than the highly toxic tetra-chlorinated dioxin that has caused health concerns in Paritutu, New Plymouth.

Although PCP was deregistered 1991, it was approved by the Environment Risk Management Authority in 2006 under the Hazardous Substances and New Organisms Act transfer of hazardous substances project. ERMA is currently reassessing PCP. No formulations of PCP are approved for use in New Zealand.

The Massey University research project looked at the health of people who’d worked in sawmills when PCP was in use. It found that the death rate for these sawmill workers was slightly lower than the national average, probably due to the “healthy worker” effect. (The healthy worker effect is that working populations are generally healthier than non-working ones, as people with illness do not enter the workforce, or leave the workforce early.) The only cause of death where the sawmill workers rated higher than the national average was in non-transport related accidents, including workplace accidents.

When the researchers compared mortality in sawmill workers who’d been exposed to PCP with sawmill workers who weren’t exposed, the data indicated a 40% increase in the risk of death from cancer for PCP-exposed workers. This result was not statistically significant, meaning the data showed indications of an increased risk of cancer, but the sample size was too small for a higher degree of accuracy. (As a result, the cancer risk from exposure to PCP cannot be ruled out.)

The researchers also found a 200 to 300% statistically significant increase in death from chronic non-cancerous respiratory disease in PCP-exposed workers. This association between PCP exposure and respiratory disease has not been shown in other research, and the result may relate to exposure to workplace contaminants other than PCP.

The 10% of workers who had relatively high levels of dioxin in their blood worked in the industry for 10 years or more, or did high risk jobs such as cleaning out PCP containers.