Another of the four sites in Auckland that have been investigated for firefighting foam contamination have been cleared.
The state-owned developer, HLC, at Hobsonville Point said it was now certain none of the now-banned foam was used at the former airbase, where about 5000 homes are being built on 170 hectares.
HLC chief executive Chris Aiken said the Defence Force had now checked its records and told HLC that firefighting training took place at nearby Whenuapai airbase, not at Hobsonville Point.
Tests had earlier cleared drinking water used by defence personnel at the Papakura defence camp and Devonport naval base.
However, it appears the groundwater has not been tested, even though at Ohakea and Woodbourne it is the groundwater that has spread the contamination by toxic firefighting foam chemicals from below the base and into adjacent bores used for drinking water.
The Defence Force is running preliminary testing of water at Whenuapai airbase.
Auckland Council chief operating officer Dean Kimpton said the council has not assessed Whenuapai.
It did not need to because the airbase was not part of a development plan for Whenuapai, he said.
The council was advised in 2016 it should include the foam chemicals - part of the PFAS family of chemicals that are very slow to break down, accumulate in the body, and are possibly cancer causing - in its checks as part of the Whenuapai plan.
As for areas outside the airbase, any development there would come under the contaminated land provisions of the Auckland Unitary Plan and the National Environmental Standard for assessing and managing contaminants in soil to protect human health, he said.
The council also had not assessed Hobsonville Point for PFAS contamination.
"Consents for the airbase area were assessed in 2014, prior to the emergence of this issue.
"As an emerging contaminant of concern it is improbable that any information relating to PFAS is on predecessor council files," Mr Kimpton said.