A national union is collecting names of past and present workers who may have been exposed to asbestos at the Halifax Shipyards, to ensure they are fairly compensated for any illnesses that can be linked to their time on the job.

For decades, asbestos was used on ships, primarily as insulation. The substance has been linked to cancer and lung diseases, and the rules for handling the material have changed over the years as a result.

Les Holloway, of the Canadian Auto Workers union, said the number of people who get sick is expected to rise because it can take years for many diseases to appear. And when they do, he said, sufferers may not think about connecting their illness back to their work.

"Any worker that works in the shipyards that falls ill with something like cancer, asbestosis and that type of thing, they automatically should be covered because where else would they have received that exposure?" Holloway said.

Thousands of people have worked at the military dockyard and the civilian shipyards over the years. The Canadian Auto Workers doesn't know how many of them are sick, but the union is trying to determine the scope of the problem by contacting current and former employees.

The compensation board in Nova Scotia says it investigates claims it is presented with.

Widespread screening called for

But Jim Brophy, an expert in occupational health in Ontario, said governments and compensation boards should be doing more to warn workers about the link between their workplace and their health.

"The compensation boards are not proactive," Brophy said. "They're not notifying people [of] what they know to be serious risk mainly because in essence they're insurance companies and they're keeping their liabilities down.

"So workers are left and their families are left to reconstruct very elaborate work histories and so it is really left to unions and health groups to advocate for these workers."

Brophy is calling for widespread screening and scanning programs for high-risk people such as shipyard workers. He said early detection would prevent some people from dying from exposure to asbestos.

Harvey Friesen, a veteran dying of lung cancer, has been urging the federal government to warn former navy sailors that they may have been exposed to dangerous amounts of asbestos on military ships.

Doctors for Friesen, who lives in Ladner, B.C., said he likely developed the cancer as a result of the two years he served in the 1960s on HMCS New Glasgow, a frigate based in Nova Scotia.