Wellington Airport says their firefighting foam does not include the toxic chemicals that may have caused contamination near two airforce bases.
The government is investigating potential contamination near Defence Force bases at Woodbourne and Ohakea, where foam containing the chemicals PFOS and PFOA were used in the early 2000s.
The government said there was no acute health risk.
Nearby residents who get their water from bores are being told not to drink it for at least a month, while tests are carried out to make sure it's safe.
Wellington Airport spokesperson Greg Thomas said it can now confirm the foam it uses has not included those chemicals for about a decade.
It had previously said it had used a foam containing PFOS and PFOA, but have confirmed the product it uses now does not contain these compounds.
He said it was taking a precautionary approach and launching an investigation.
The airport is now undertaking site-wide testing on the historic use of firefighting foam.
Mr Thomas said preliminary investigations showed there were no groundwater-based drinking water sources in the airport vicinity.
Meanwhile, Refining NZ confirmed PFOS and PFOA based foam has not been used at the Marsden Point Refinery since the mid 2000's.
Its chief executive, Sjoerd Post, said the decision was made to carry out groundwater and soil tests around the refinery's fire training ground, after the story about the use of the foams was reported in Australian media earlier this year.
"Those tests show that PFOS and PFOA levels are at, or below the HEPA guideline values for both drinking water and for environmental protection," he said.
