But he also said there was a lot of anxiety caused by misinformation

HEALTH officials don't know the long-term effects of exposure to smoke will have on residents living near a Victorian coal mine that burned for 45 days, a senior health official says.

But he also said there was a lot of anxiety caused by misinformation.

State health commander Chris Brook said it was unlikely there would be long-term effects from exposure to the Hazelwood mine fire smoke, but a study was needed.

"The literature at best suggests that it's unlikely there are long-term effects but you are right, there is a gap," Mr Brook told an inquiry into the blaze on Tuesday.

"That's a gap that we are attempting to close."

Some Morwell residents left after the fire shrouded the town in smoke and ash after it ignited on February 9.

The CEO of a local asbestos support network, Vicki Hamilton, said the department gave mixed messages about the smoke, including saying there would be no long-term health effects.

"My understanding is there has been no fire like this that I know in Australia so how can you say there are no longer-term health effects?" Ms Hamilton said on Tuesday.

"I had members ringing me up and saying to me 'is there a study out there that shows that' and I'm going 'no I don't know of one'."

Mr Brook said it was difficult for the department to communicate its message to Morwell residents during the fire because it was not believed.

He also said "high levels of anxiety" were caused by misinformation, such as concerns about heavy metals being present in the smoke.

"Latrobe Valley brown coal is not a pollutant source for heavy metals," Mr Brook said. "It just isn't."

Community submissions to the inquiry reveal many residents suffered headaches, nose bleeds and those with existing conditions, such as asthma, found their health had deteriorated.

Mr Brook said there was no statistical increase in the number of people presenting to the local emergency department or calling ambulances, but more than 2000 people were assessed at a community health centre set up to respond to the fire.

The inquiry earlier heard air pollution was 10 times the acceptable levels during the peak of the fire, but scientists weren't able to measure it accurately at the time.