Chemicals used in firefighting foam that spewed out of a Brisbane Airport hangar and escaped into the stormwater system have caused fears "worldwide", the state government warns.

Queensland Environment Minister Steven Miles said the spill was "very substantial" and the state government was in the process of phasing out the chemicals used in the foam after they were recently banned in Queensland.

But the airport site is controlled and regulated by the Commonwealth, which hasn't banned them.

Nevertheless, Dr Miles said the incident should "send a message" to industries throughout Queensland, irrespective of their governing body, that they should dispose of the firefighting foam if they have it.

"This is a chemical that has caused concern worldwide," Dr Miles said on Friday.

The Queensland government confirmed about 22,000 litres of the foam was released from a failed deluge system within the Qantas hangar on April 10.

While about three-quarters was contained, some of the remaining portion appeared to have seeped into the wider environment and caused the deaths of 20 nearby fish.

Health authorities are now warning people to avoid eating seafood from or fishing near the potentially contaminated area around the lower reaches of the Brisbane River, from Bulimba Creek to Fisherman Island, and north to Shorncliffe.

It's believed the foam contained perfluorooctanoic acid (PFOA) but chief health officer Dr Jeannette Young said there was "no consistent evidence" that exposure posed a threat to humans.

"(But) I understand this was a significant spill (and) avoiding seafood consumption from the impacted area in the short term is a sensible, cautious approach," Dr Young said.

Dr Miles echoed the sentiment, and said the government's warning was being issued as a precaution, with tests results due back next week to determine conclusively if the dead fish were killed by the foam spill.

A joint investigation between the Queensland and Commonwealth governments was under way and environmental officers had taken water samples from the polluted site.

AAP