By TONY GEE
KAITAIA - Air quality tests near houses downwind of the Juken Nissho triboard mill in Kaitaia have revealed the presence of two noxious chemicals but the source of the chemicals is not clear.
The Northland Regional Council says the chemicals, HDI (hexamethylene di-isocyanate) and TDI (toluene di-isocyanate), are associated with spray-painting work.
"At this stage, we have no evidence as to the source of these chemicals," said council monitoring manager Tony Phipps.
There are several panelbeating and car-repair businesses within a kilometre or so of the mill.
However, results will be known soon of tests of the plant's chimney-stack gases. Mr Phipps said they should show whether the concentrations of HDI or TDI were coming from different resins now being used in the triboard manufacturing process at the mill.
Concentrations in the air of the two chemicals were "relatively low, but still of concern."
If it is established that HDI and TDI are being released from the triboard operation, it is likely that Juken Nissho will be told to stop using the new resin and apply for a new resource consent.
The company's current consent controls only the amount of total aldehydes, including formaldehyde, which can be emitted. It does not cover MDI (methylene diphenyl di-isocyanate) or any other chemicals which might be released as a result of using the new resin.
It is MDI and its associated polymerised version, PMDI, used in new resin at the plant, which have sparked health concerns among residents living near the mill.
A Kaitaia doctor has told health officials in Whangarei about four cases of people said to be suffering symptoms from the effect of possible exposure to isocyanate-related toxins.
The concerns of residents were followed up at a mill community liaison meeting after the stack emission tests.
The meeting, involving Juken Nissho representatives, residents and council and Northland Health officers, was told that routine air sampling had so far shown no sign of MDI in air around the mill but that testing had revealed the presence of HDI and TDI.
Mr Phipps said every effort had been made to ensure that stack emission tests, carried out by independent consultants, were representative of the mill's normal production process.
Samples of resins being used were also collected along with product samples taken at various stages of the board production.
Meanwhile, public submissions closed yesterday on Juken Nissho's resource consent application for air discharges from proposed extensions to the mill.
The regional council will hold a public hearing in Kaitaia later this year to consider submissions on the planned extensions and whether the effects of gas discharges into the surrounding environment will be acceptable.
Council tests for source of air toxins
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