Hazard for firies acted on: Vic fire chief

Victoria's fire chief denies union claims that warnings firefighters were being exposed to hazardous material at a coalmine were ignored.

The United Firefighters Union (UFU) says a leaked letter, dated February 13, was not passed on to firefighters working on the Hazelwood open-cut mine fire, where they were exposed to dangerously high carbon monoxide levels.

Fire Services Commissioner Craig Lapsley said February 13 marked the turning point where the fire became a hazardous materials incident.

"It meant that we were using hazardous-materials procedures to work on a fire that is not normal," Mr Lapsley told reporters on Monday.

UFU national secretary Peter Marshall said he believed firefighters were treated like canaries in the mine, with no clear justification for determining the carbon monoxide level at which it was safe for crews to enter.

"The CFA and MFB's (Metropolitan Fire Brigade) consultants say firefighters were unnecessarily and knowingly exposed to high levels of carbon monoxide that could've been, and knowingly are, detrimental to their health," Mr Marshall told ABC Radio.

Mr Lapsley said that in the first few days of battling the mine fire 17 firefighters were detected with elevated levels of carbon monoxide.

Authorities then sought and acted on advice by a peer-review panel, with the measurement of carbon monoxide validated by the chief health officer and the EPA.

Firefighters were also given detectors to mitigate carbon monoxide risks in pockets of the mine, Mr Lapsley said.

"I don't believe at all that we've compromised anyone's safety. I think we were very dynamic about what we were dealing with," he said.

The fire chief said the terms of reference of an independent inquiry into the fire are broad enough to tackle issues concerning the response by fire services.

Sixty per cent of the coalmine has been declared safe after the fire but two other areas of the mine are still being worked on.

The blaze began on February 9 when a deliberately lit fire spotted into the mine.