The ash blowing over Port Augusta from a closed power station does not contain asbestos, South Australia's environmental watchdog says.
The Environmental Protection Authority SA analysed the fly ash over the weekend after a former power station worker raised concerns about it containing the harmful substance.
EPA chief executive Tony Circelli on Monday announced the results of testing on several samples recently taken from the ash dam, saying no traces of asbestos were found.
"We concluded that there are no asbestos fibres seen," Mr Circelli told reporters, adding that the full results of the testing would be released on Tuesday.
The ash is a by-product of the coal-fired Northern Power Station, which was closed by Flinders Power last May, and it has recently been whipped up from a dam at the site and into the air.
Meanwhile, the state government announced it will provide free health checks to Port Augusta locals who are worried about the ill effects of breathing the ash dust.
Manufacturing Minister Kyam Maher said the government would foot the bill for the checks for now but he had asked Flinders Power for reimbursement since the company was responsible for managing the dust.
"It's not good enough that these dust clouds are eventuating in Port Augusta and we understand that people are concerned about health issues with dust," he said in Adelaide.
The minister said Port Augusta residents would able to arrange an appointment with a health professional using a hotline or see their own general practitioner for free.
He said while there's no evidence the dust contains toxic or harmful materials, breathing any sort of dust could be problematic for people with asthma or respiratory problems.
Opposition health spokesman Stephen Wade said local doctors were already under the pump and would not be able to cope with the influx of free checks.
"People are experiencing adverse health effects now. They can't wait until the end of February or March to get an appointment with their GPs," he said.
Mr Wade called for the government to establish clinics in the area with public health physicians to administer the checks.