Asbestos surgery fears
Justin Betteridge believes a chunk was in his car after bits of asbestos were found along 2km of the rail corridor.
Some workers on the $96 million project have also been issued with personal monitoring devices that will show if they are exposed to fibres.
Employees returned to work last week after WorkSafe inspectors lifted a prohibition order, which had closed the site since the previous Tuesday.
WorkSafe is satisfied the site run by United Group Limited Infrastructure has been cleaned, but is investigating how and when the asbestos was uncovered, less than 30m from Roxburgh Park homes.
A spokesman said it was too early to decide whether any charges would be layed under the Occupational Health and Safety Act, which carries fines up to $943,000.
But Mr Betteridge has been unable to return to his job.
He said his employer and the Construction, Forestry, Mining and Energy Union had not yet arranged for him to do a compulsory safety course, which other union members on site had completed.
"I've been told there's no course available until Wednesday, maybe Thursday," he said.
"I am wondering what will happen to me because I've alerted people to the danger."
He said he had also received anonymous threats by phone and had been warned of "accidents" on site.
Mr Betteridge said the asbestos was discovered early on November 21 after his group had been working in the area for a fortnight.
He said employees were not notified until the next day after WorkSafe inspectors arrived.
He informed a school and nursing home near the track as WorkSafe inspectors shut the site.
An initial WorkSafe report found a grader had run over bits of asbestos sheeting on an access track. Breaking the material may have dispersed potentially lethal fibre dust in the wind.
Mr Betteridge said a specialist had booked him in for surgery at the Austin Hospital to check if his lungs and airways were free of asbestos fibres, which can cause mesothelioma.
A United Group spokeswoman said the company could not comment.