KEY POINTS:
Builders and carpenters are "coughing up blood" after working with timber which has undergone a chemical treatment banned in the United States.
The treatment - to preserve wood used in frames of most of the 25,000 homes built each year - is also causing headaches, skin rashes and nose bleeds.
National yesterday demanded an urgent inquiry into the health and environmental risks.
Bob Clarkson, associate building spokesman, said if the treatment was found to be the root of the problems, it should be banned.
"How did this stuff ever get on the market when these are the results?"
Timber treatment was regulated after the leaky buildings scandal. The wood is treated with light organic solvent preservatives (LOSP). The solvent carries the preservative - such as tributyltin naphthenate (TBNT) - into the wood then evaporates.
TBNT is a toxic, corrosive fungicide which has been banned as a timber treatment by the US Environmental Protection Agency.
Matt Hill, who runs a small construction company in Wellington, said he had been coughing up blood in the mornings and suffered bad headaches.
"We've been cutting timber for years, and suddenly it's dangerous. I thought problems like this had been sorted out years ago," Mr Hill said.
"It's going into people's houses, so what long-term effects could there be?"
The Herald revealed some of the adverse health effects earlier this year, but Mr Clarkson said nothing had been done since.
He said he was writing to the Environmental Risk Management Authority asking for a review of the treatment under the Hazardous Substances and New Organisms Act.
He was also contacting the Department of Building and Housing and the Occupational Safety and Health service.
Mr Clarkson said safer alternatives were on the market.
"We want safe and proper timber treatment that will ensure houses don't rot, but also do not cause serious health problems for our builders," he said.
The Government had contributed to the problem with rules that were too complicated, with at least five different types of treated timber having to be used in different parts of houses, Mr Clarkson said.
Kevin Hing, executive officer of the Timber Preservation Council, said part of the problem had been the high demand for timber for the booming housing market, which meant it was not always given the recommended four days "breathing time" to allow chemicals to dissipate.
The council had asked merchants to send out a form with treated timber advising how much time was needed to allow that to happen.
Mr Hing said the council had also issued guidelines for working with LOSP wood, including wearing gloves, goggles and a dust mask.
But Pieter Burghout, chief executive of the Registered Master Builders Federation, said the safety advice was impracticable.
"Can you imagine builders trying to get a job done in gas-mask type respirators?"
It was "foolish" to continue using the treatment in New Zealand if other countries had banned it.
However, he said complaints about health problems were dying down as the industry began to favour different, less toxic, treatments.
