The elderly, young children and pregnant women were advised on Friday to evacuate an Australian town that has been shrouded by smoke and ash from a burning coal mine for almost three weeks.

Victoria state Chief Health Officer Rosemary Lester said vulnerable residents were advised to leave the town of Morwell as a precaution because the fire in the nearby Hazelwood Coal Mine is expected to spew smoke for at least 10 more days.

Residents of Morwell, a town of 14,000 in the Latrobe Valley east of Melbourne, have complained of chest ailments and headaches caused by the acrid smoke.

Lester said that health workers had not yet seen serious health effects from the smoke, and that there had not been a sharp increase in ambulance calls or hospital admissions.

“But we do know that the longer the vulnerable people spend in the fine particles from the smoke, that that’s a continuing risk to them,” she said.

In addition to people aged over 65 years, under school-age children and pregnant women, Lester advised people with pre-existing heart and lung problems to temporarily leave town.

Graeme Middlemiss, a Morwell resident an elected member of the local council, said some people had already left town because of the smoke and that authorities should have been quicker to respond to the health dangers.

“The town has been choked with smoke. For the first two weeks it was appalling and a constant rain of ash,” Middlemiss told Australian Broadcasting Corp.

Police suspect an arsonist started the blaze in the open-cut coal mine with three brush fires lit on Feb. 9. The fire has since burned deep into the coal seam.

Fire Service Commissioner Craig Lapsley said it could take another 10 days to bring the blaze under control so that it wouldn’t send significant smoke or ash over Morwell.