Air pollution was 10 times acceptable levels during the peak of the Morwell coalmine fire in Victoria, but scientists were unable to measure it accurately at the time, an inquiry has heard.
Staff from the state’s Environment Protection Authority (EPA) who were sent to measure air quality near the Hazelwood mine fire were using a tool that was not calibrated for coal fires when the smoke levels peaked on 15 and 16 February, the inquiry into the blaze was told.
The EPA’s assessments and predictions expert, Paul Torre, said indicative data was passed on to the Health Department on the weekend of 15 February but more accurate data wasn't able to be generated until several weeks later.
"Some of the data of the 15th and 16th was actually estimated several weeks later or a month later," Torre told the inquiry on Tuesday. "We weren't able at that time to provide that information.
"We were just providing air quality forecasts."
A report produced after the fire showed that over 45 days of air-quality monitoring, from 14 February to 31 March, the level of particles known as PM 2.5 in the air exceeded the acceptable standard on 21 days.
On seven days levels were hazardous and on four days levels were extreme.
On the weekend of 15 February the concentration of smoke particles was greater than 250 micrograms per cubic metre, 10 times the acceptable standard, the inquiry heard.
Torre agreed the indicative data was "accurate enough" to inform the response by emergency personnel during the blaze but said the experience highlighted the need for the EPA to have a rapid response capacity.
"We're not really geared up for our role in this emergency response space," Torre said.
The inquiry heard on the weekend of 15 February, EPA scientists were using a piece of equipment known as DustTrak that had to be hired from Tasmania.
"The calibrations the Tasmanians had done was with wood smoke. We wanted to do a bit more calibration," Torre said. It had been deployed as quickly as possible, he said.
The six-week mine fire that ignited on 9 February shrouded Morwell in smoke and ash, forcing some residents to evacuate.
The DustTrak equipment was monitoring air in Morwell south in addition to EPA equipment at east Morwell.
