A world-first trial using Victorian firefighters has found a way to reduce blood levels of potentially harmful chemicals often present in fire-fighting foams.

A world-first clinical trial, undertaken by Macquarie University and Fire Rescue Victoria, found that regular blood or plasma donations can reduce PFAS levels in blood.

It is the first time an intervention has been found to reduce PFAS levels.

PFAS, known as per and polyfluroalkyl substances, are a group of synthetic chemicals used in industrial and consumer products that can make people sick.

Fire Rescue Victoria Assistant Chief Fire Officer Mick Tisbury, who has advocated for many years on PFAS minimisation in the fire and rescue service and developed the initial idea for the study, said the findings were a positive result for firefighters.

"Firefighters often put the health and safety of others before their own health, so it is pleasing that the results from this research can be used to improve the health of firefighters who have acquired high PFAS levels through vital community work," Mr Tisbury said.

"It's important to also recognise the firefighters who volunteered their time to participate in this important study. The findings will not only benefit the firefighting community but others working in high-risk sectors who are exposed to PFAS chemicals.

"This research will provide vital intelligence on reducing the impacts of PFAS and will now be shared throughout Australia and internationally so that others may benefit, act on this knowledge, and advance this important work."

Firefighters have historically been exposed to firefighting foams that contain high levels of PFAS and have previously been found to have higher blood PFAS levels than the general population.

Lead author of the study, published in JAMA Network Open on Monday, Dr Robin Gasiorowski, Senior Lecturer in Haematology at Macquarie Medical School, said blood and plasma donation could be simple interventions for people with elevated PFAS levels.

"The results from the study show both regular blood or plasma donations resulted in a significant reduction in blood PFAS levels, compared to the control group," Dr Gasiorowski said.

"While both interventions are effective at reducing PFAS levels, plasma donations were more effective and corresponded to a 30 per cent decrease."