Timber treatment under review

Wednesday 18 May 2005

Solvents used to treat timber before it's fumigated may be responsible for symptoms experienced by some Port Nelson workers.

The Department of Labour reviewed fumigation operations at the port in March, to evaluate possible methyl bromide exposures to workers during the fumigation process and subsequent ventilation of the shed.

DoL national operations manager for health and safety, Mike Cosman, said the audit uncovered the presence of substances other than methyl bromide, which were much more likely to be responsible for making people feel unwell.

People claiming to be exposed to methyl bromide at the port had often complained about smelling something unpleasant and immediately reported stinging eyes, tingling lips and sometimes breathlessness, he said.

'That set off alarm bells, because methyl bromide is completely odourless and acute exposure to it causes feelings of nausea many hours later - different symptoms entirely to what was being reported.

'That suggested to us that there was something else at the port that was affecting people.'

Atmospheric monitoring at the port identified background levels of 'volatile organic compounds' (VOCs), including solvents used in timber preservative treatments and diesel fumes, before and after fumigation.

Mr Cosman said meters were picking up the presence of VOCs before fumigation had even begun, quite often in high concentrations. 'These readings were clearly not associated with methyl bromide, and the detection of these substances could explain the 'smells' coming from the timber stacks, and the symptoms people were complaining about.'

He said people working in premises around the fumigation sheds that had reported these symptoms had been examined, and there seemed to be no lasting health effects.

DoL is now planning to thoroughly investigate what solvents and preservatives are being used in the treatment of timber, and to establish more definitively what their potential health effects are.