Triboard mill emissions at safe levels

By TONY GEE

A United States report shows that the Japanese-owned Juken Nissho triboard mill in Kaitaia is producing only very small amounts of controversial chemical emissions.

The report from Centre Analytical Laboratories showed gas emission samples from the mill's wet scrubber process contained detectable amounts of methylene diphenyl di-isocyanate (MDI) at levels of only 7 per cent of US Environmental Protection Agency guidelines.

Triboard mill technical manager Scott Earnshaw said yesterday that this was the equivalent of 0.5 parts of MDI per billion from a chimney stack.

It could be compared with an Occupational Safety and Health workplace safety level of six parts per billion.

The report found no evidence of two other associated isocyanate chemicals in gas emission samples taken from the mill - toluene di-isocyanate (TDI) or hexamethylene di-isocyanate (HDI), which had also been the subject of earlier concerns.

But the company has told the Northland Regional Council it is trying out a new formaldehyde technology which can meet technical requirements for triboard adhesives without using isocyanate resins.

This would allow the mill to stop using polymerised MDI adhesives within about three months, Mr Earnshaw said.

Trials last year with new formaldehyde technology had produced good results.

"They showed we can do without isocyanate adhesives, although we still have to prove it with more testing," he said.

Gas emission and resin samples were taken at the mill site last August and October in response to council queries over possible chemical pollutants in air around the mill during the triboard manufacturing process and its use of isocyanate-linked resins and adhesives.

At the same time, Kaitaia doctors notified the cases of 13 patients living near the mill to Whangarei public health authorities.

All were suspected of becoming ill through exposure to airborne chemicals.

The patients were referred to specialists for medical reports, most of which are now in the hands of the Northland Medical Officer of Health, Dr Jonathan Jarman, who will report on the issues next month.

Last year the council ordered Juken Nissho to stop discharging potentially harmful isocyanates into the air by November 3 in an abatement notice served on the mill.

But the company effectively ignored the notice, saying it was not discharging isocyanates because it was not using MDI in its manufacturing process.

Yesterday, the company said it approached Centre Analytical Laboratories and Bayer US after what it described as "a hashed" emission test and draft report from a New Zealand laboratory that showed detectable isocyanate emissions.

The New Zealand company later acknowledged errors in its report, which was sent to the regional council. An executive summary report obtained by the Herald yesterday said both August and October wet-scrubber samples from the site contained MDI after testing by the American laboratory.

October samples sent to Bayer have also indicated detectable levels of MDI, although the summary says the Bayer analysis is not yet complete.

In its press statement, however, the company said Bayer had reported zero isocyanate emissions.

Dr Jarman said yesterday that there was still not enough evidence to say definitely that emissions from the mill were likely to harm humans.