Ambient air ammonia gas (NH3) outside the former Carter Holt Harvey Mataura paper mill, where 10,000 tonnes of Ouvea premix is stored, is almost undetectable, a report says.
Monitoring is being carried out at 15-minute intervals 24 hours a day, seven days a week.
The Ouvea premix is being stored in the building by Taha Asia Pacific, which gained a resource consent to store the material there until January 11 next year.
But the company went into liquidation in August last year.
The resource consent only called for monitoring outside the building and that limit was set at five parts per million (ppm), Gore District Council chief executive Steve Parry said.
While there was no limit set for inside the building and no obligation to monitor there, the council and the liquidator decided to go the extra mile, Mr Parry said.
The average ambient air ammonia levels inside the building were just above the outside threshold, he said.
A monitoring report compiled by e3 Scientific said there was a strong variation in the indoor NHas the day warmed up.
The report noted that while the indoor sensor detected up to 16ppm of NHmedian concentrations for the initial three weeks of monitoring were 6.1ppm and 5.8ppm, respectively.
“The outdoor sensor remains below the limit of detection (2ppm) over the three-week period, with Photo Imaging visiting the site to confirm the validity of the outputs from the outdoor sensor in the week of the 4th of December,” the report stated.
“So there is no issues with ammonia levels compromising people’s health,” Mr Parry said.
The result from the outside monitoring was pleasing, he said.
The liquidator paid the lion’s share of the cost of installing the devices, Mr Parry said.
The monitoring data was posted on the council’s website.
Mataura resident Laurel Turnbull said residents had been asking for monitoring data for some time and had not received it.
“It was supposed to be done from day 1 and it hasn’t been done,” she said.
She was sceptical about the low outside readings, and residents living near the site suffered health effects, she said.
“How come people are getting headaches and have breathing problems?”