KEY POINTS:
Nelson residents who may have been exposed to dangerous levels of a toxic fumigant are demanding more be done to discover how they may be affected.
The call from anxious members of the Nelson Waterfront Residents Association comes after previously confidential reports were released stating that methyl bromide,
used at Nelson's port, may have exceeded safety standards as it drifted into the nearby Port Hills suburb.
A group of widows believe the fumigant is linked to the deaths of their husbands, who worked at the port, from motor neurone disease. But a study by Nelson's medical officer of health, Ed Kiddle, found no link between the gas and the men's deaths.
In October, a parliamentary select committee recommended stricter controls on the use of the chemical after more than 1400 people signed a petition for it to be banned.
Auckland-based Air and Environment Science's Craig Stevenson in his report said there was a likelihood gas from the port may have exceeded safety standards as it drifted into residential parts of the surrounding hills.
He said more testing and analysis was necessary.
Spokeswoman for the residents' association, Fiona McLeod, told the Herald that residents of the Port Hills area were concerned but knew nothing for certain as yet.
The association wanted a full assessment on the potential health effects on residents and that "serious consideration" be given to restricting use of methyl bromide when winds were blowing towards the area.
Modelling used in Dr Stevenson's reports predicts that after a three-minute discharge from Shed Two at the port under "worst-case meteorological conditions", concentrations of methyl bromide could be as high as 581 milligrams per cubic metre in parts of the Port Hills.
This is more than twice the level of 285mg allowed under workplace exposure standards.
Methyl bromide is used in agriculture to kill pests including micro-organisms, insects and weeds. It is mainly used to fumigate infested imported goods, and as a pre-shipment treatment for some exports including fruit and wood, and by horticulturists to fumigate soil under susceptible crops.
Fumigation was moved to Shed Three, which is further away from the hills, in 2005. But the reports indicated that discharge levels from Shed Three could still be too high.
Dr Stevenson wrote that further assessment could conclude that only a "low probability" of exposure existed.
The reports were only released after a ruling by the Environment Court. The ruling was hailed by the Campaigners Against Toxic Sprays (Cats) group.
Chairwoman Claire Gulman hoped the reports would create public pressure for a methyl bromide ban.