Qantas will stop using a toxic firefighting foam after thousands of litres spilled from a hanger into the Brisbane River earlier this year.
A faulty pressure gauge at the airline's Brisbane hangar has been blamed for spilling about 22,000 litres of the toxic substance in April, with roughly one third believed to have entered local waterways.
Protective barriers designed to contain any spill also failed.
Qantas says it has compensated commercial fishers affected by the subsequent fishing ban, and within 12 months will switch nationally to foam that doesn't contain a toxic group of chemicals known as PFAS.
"The foam spill at our Brisbane hangar in April was deeply disappointing and falls well below the environmental standards we set for ourselves," Qantas said in a statement on Friday.
The airline says the faulty gauge has been fixed, and systems and procedures have been improved to ensure it doesn't happen again, but added local waterways have been contaminated from other sources.
Tests following the April 10 spill, including upstream sites, revealed "the presence of PFAS from a variety of sources, including sources unrelated to the spill from our hangar earlier this year", Qantas said.
In May, the environment department gave fishers the all clear to return to grounds near the airport, saying tests on seafood were "below investigation trigger levels".
In July last year, the Queensland government announced a ban on firefighting foam containing PFAS chemicals because of their potential to cause significant environmental harm as they break down very slowly.
PFAS have been used since the 1950s in a range of common household products, such as non-stick cookware and fabric, as well as industrial products.
The chemicals are no longer directly used in consumer goods, but are commonly found in the environment at low levels due to their historical use.
It's also common for people to have low levels in their blood, due to everyday exposure.
The full effects of PFAS exposure on human health are not currently known, but authorities say adverse outcomes can't be excluded.
Firefighting foams containing PFAS have also been linked to contamination around air force bases at Oakey in Queensland and Williamtown in NSW.
