Under the heading "worst foreseeable outcome" for workers who use the tunnels, the assessment states: "Develop cancer over a period of years."
The Domain and Burnley tunnels opened in June 1999, raising fears that some workers could be close to showing signs of illness.
But CityLink and the RACV have rejected the report, saying that the tunnels met WorkSafe standards.
The RACV, which is contracted by CityLink to run its incident response trucks, have provided masks that do not seal around workers' mouths to protect them from the fumes.
State secretary Steve Dargavel said staff deserved to be given more than simple painting masks to protect health.
"The fact that the company has refused to provide effective protection is a disgrace," he said.
Mr Dargavel said he believed CityLink was concerned the heavy-duty breathing masks would highlight the poor air quality in the tunnels.
RACV general manager Guy Hummerston said air quality was monitored in tunnels.
heraldsun.com.au 14 Nov 2012
The government is also concealing the reports that scientists have put out with respect to the pollution emanating from the Sydney's tunnel's air vents and how they are effecting residents.
Another coverup by government in the name of business / profits.