A top Taranaki health official says authorities need to do more to ensure Eltham's rotting buttermilk pit isn't emanating dangerously high levels of toxic chemicals.
Taranaki medical officer of health Dr Jonathan Jarman said the South Taranaki District Council must launch a robust gas monitoring programme so its potential health risks could be fully understood.
Council chief executive Craig Stevenson agrees.
Mr Stevenson said they would now conduct a more comprehensive air quality monitoring programme, so health professionals "could make a better assessment of whether the gas coming from the eader is dangerous to human health".
Last year, Fonterra dumped about three million litres of the milk byproduct, along with another 150,000 litres of milk tainted with drilling wastes, at the plant in an effort to deal with spring's record milk production.
But as the milk broke down, people living near the plant were swamped by a sickening smell.
Residents have complained of headaches, tiredness, worsening asthma, aching muscles and depression during the four-month-long assault on their nostrils.
Dr Jarman said the most likely scenario was that the odours were making people sick.
"But there is a small chance that some of the chemicals being released by the anaerobic digestion, including acids such as hydrogen sulphide, are at the levels that those gases can directly cause adverse health effects."
Dr Jarman said doctors who had approached him believed their patients had illnesses caused by the objectionable odours.
"To me this sounds more serious than just a bad smell."
Mr Stevenson said while he too believed the most likely impact to health was caused by a "reaction to the odour", more robust evidence was needed.
"I want to assure them we are doing all we can to get the situation fixed as quickly as we can."
He said council had also conducted three independent analyses of gasses under the eader cover and staff were regularly monitoring hydrogen sulphide levels at the plant.
Council has been pumping gas off the eader at up to 110,000 litres per hour, while at the same time pumping waste into a nearby aerobic pond for treatment. Mr Stevenson said they were also looking at ways to speed the process up.
- Taranaki Daily News
Should NPDC sell its Tasman farms?Related story: Tasman farms in black