A warning was issued to all members of the ACT Emergency Service Agency and the commissioner Dominic Lane after a CSIRO study found "unexpected levels" of the chemical in protective clothing.

The study also found formaldehyde – which is considered as a probable human carcinogen by Safe Work Australia – was released into the air when the clothing items were stored in a sealed environment.

Formaldehyde was used when firefighters' protective clothing was treated with Proban – a chemical additive known to fire-proof fabrics, the warning said.

"A number of uniforms used by ESA personnel, particularly the ACT Rural Fire Service, use personal protective clothing treated with Proban," an ESA spokesman said.

"Based on the CSIRO results and the ESA operational practices it is not considered a health hazard for the ESA, however, it is important that further research is conducted."

ACT firefighters have been warned they may suffer skin irritations and negative health affects should they breathe in the fumes emitted from the garments.

"Wherever possible, Proban-treated [clothing] should be stored in a well-ventilated environment but if this is not possible precautions should be taken to avoid breathing in fumes emitted when opening the confined space," the alert said.

"The known incidence of skin irritation time that Proban-treated cotton has been used in Australia is minimal.

"Where there is evidence that skin irritation is occurring when a Proban-treated over-garment is being worn, individuals should wear long-sleeve shirts and long pants underneath these garments."

ESA members were also urged not to shake dirty or soiled garments after use and to wash the protective clothing separately on each occasion.

Formaldehyde is a naturally occurring compound released during bushfires.

An earlier Monash University study of 230,000 present and past volunteer firefighters showed no elevated levels of formaldehyde-linked cancers compared to the general population.

The warning issued to ESA members – along with 74,000 members of the NSW Rural Fire Service – said formaldehyde was naturally present in the air we breathe and in the foods we consume.

"In addition, a wide range of human domestic and industrial activities are responsible for both direct and indirect release of formaldehyde into the atmosphere.

"It dissipates quickly when left in a well-ventilated environment."

The warning said further testing was required to translate the findings into "an operational environment and to establish any other potential exposure to our members".

with Daisy Dumas