A banned toxic firefighting foam used at commercial airports has contaminated surface water and soil in Palmerston North.
Authorities say people should avoid gathering food such as watercress in the area and anyone who lives near the airport and who does not tap into the city water supply should be careful.
Samples were taken from land at Palmerston North Airport earlier in the year after it was confirmed foam containing banned chemicals was found in fire trucks and in storage at the airport, as well as at airports in Napier and Gisborne.
* Testing for contamination begins at commercial airports after banned firefighting foam found * Toxic foam found in fire trucks and storage at three more commercial airports * Nationwide investigation into toxic firefighting foam launched​ * Testing area for Ōhakea toxic foam contamination to be extended This type of foam, which is mostly used in training to fight fuel fires, was banned in 2006 as it contains harmful chemicals.
Palmerston North Airport chief executive David Lanham said the results from the samples tested at the airport were received last week and showed higher levels of the banned chemicals in soil and sediment samples.
The seven surface water samples all recorded levels above the interim drinking water guidelines.
Firefighting foam containing the toxic chemicals was used at the airport for fire training purposes up until the late 1980s.
"With technical support and local knowledge about bores and groundwater from Horizons Regional Council, [we] engaged a contractor to test airport sites earlier this year."
Palmerston North City Council chief executive Heather Shotter said the affected waterways were not used for water takes and all drinking water bores on the city supply were tested in April 2018 and given the all-clear.
​MidCentral DHB said exposure to the toxic foam would not cause acute health problems.