Air force personnel had to be “temporarily released” from their duties and BAE systems workers were relocated to another area a fortnight ago, after Strontium Chromate was found during “routine” workplace testing. 

A Defence spokesperson said the area where the chemical was found has now been cleaned up, but would remain off-limits until test results came back.

Dr Mariann Lloyd-Smith, a senior advisor to the National Toxics Network, said the development showed the problems with the RAAF base were bigger than the contamination from firefighting foams containing perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA).

"This isn't the first time they have a contamination issue and it won't be the last," she said. 

"I think now you'd be asking what else is on the base? What else are they not telling us? 

"It's not just a PFOS/PFOA issue. It's a contamination issue at the base." 

Strontium Chromate is a yellow substance used for aircraft maintenance, due to its anti-corrosive properties. 

It has been classified as a human carcinogen by the International Agency for Research on Cancer and can increase the risk of lung and nasal cancer. 

A Defence spokesperson said the amount found was "well below safe limits for dirty areas." 

But Dr Lloyd Smith said the comment needed to be clarified because Australia has not set health investigation levels for the chemical. 

"I was at a loss as to what they were talking about," she said. "People deserve a better explanation.”

She said the risk to workers was unclear because Defence had not identified how the chemical had been used. However the spokesperson said personnel followed “appropriate personal protective equipment and work hygiene practices.” 

Spokesperson for the Australian Manufacturing Workers Union Joe McKenzie said it was “closely monitoring” the situation.