In an unpleasant surprise for firefighting foam investigators, the toxic chemicals have now been found in the drinking water of a Rangitikei town.
Photo: 123RF The Health Ministry said the chemicals were at levels well below maximum safety guidelines and Bulls water was still safe to drink.
"We didn’t expect to find any trace of contaminants, and nor did the Ministry of Defence," Mr Watson said.
Mr Watson said the fifth clear bore was the largest source of drinking water, and was being cranked up to supply more as the second round of tests was carried out.
He said one theory was the contamination might be linked to firefighting at a Skyhawk crash site in the 1980s.
The chemicals are very long lasting.
The first round cleared the town supply.
The latest health advice from the US Environmental Protection Agency – where the research is probably the most advanced – about exposure to the PFAS class of chemicals, including those found in firefighting foam, was cause for concern.
"Studies indicate that PFOA and PFOS can cause reproductive and developmental, liver and kidney, and immunological effects in laboratory animals.
New Zealand’s drinking water guideline maximum for PFOA is eight times higher than for PFOS.