Ontario Environment Minister Jim Bradley has stepped into the fray over who should clean up Hamilton’s contaminated airport.

A consultant has spent the year studying perfluorooctane sulfonate (PFOS) pollution and cleanup options at the city-owned airport, where firefighting foam laced with the chemical was used in training 30 years ago.

But city council and the federal government, which owned the airport until 1996, are wrangling over responsibility for the cleanup, which could cost up to $4 million. The federal government has denied responsibility, pointing to a 1996 land transfer agreement.

But a letter from Bradley dated Nov. 6 asks Transport Canada for “active participation in the remediation of the Hamilton International Airport” as well as a downstream study of the chemical, which has been found in high amounts in wildlife in the Binbrook reservoir.

This letter marks the first time the province has publicly pushed its federal counterpart to clean up the airport. Local ministry officials had previously only asked Transport Canada to help with a downstream study.

Mayor Bob Bratina said he talked to Bradley in August about the cleanup dilemma and the need for a “multijurisdictional” effort. He said it’s “not satisfactory” for any level of government to deny responsibility for a potentially “large, public environmental issue.”

A Transport Canada spokesperson wasn’t immediately able to say Friday if the letter had been received. The federal agency now has more time to decide, however.

Geoffrey Knapper, a Ministry of the Environment (MOE) district manager, said Friday he has asked airport manager Tradeport to do more testing to prove its pollution cleanup plan will actually work.

Tradeport recently submitted the results of new testing and a remediation experiment to the MOE in the hope of presenting an approved plan to council in November.

That won’t happen now, Knapper said. “We need more information to determine whether the remediation technique is appropriate.”

The work and ministry evaluation is expected to take three months.

The ministry has also asked Tradeport to create a no-farming “buffer zone” around ditches leading away from the contaminated site after local biologist Joe Minor raised concerns about crops grown on the property.

Minor applauded the minister’s letter.