A doctor who died last week of leukemia claimed he became ill because of poor ventilation in a building he worked in for years at McGill University in Montreal.

Dr. Barry Mishkin was 34 years old.

Michkin believed the years he spent working and studying in a medical building were the cause of his acute lymphacytic leukemia, which was diagnosed in March, 1999.

Benzene is used to manufacture synthetic rubber

Two other doctors who worked in the lab during the 1990s now have leukemia. They all claim they were exposed to dangerous levels of benzene, a chemical known to cause leukemia in humans.

Lawyer Gordon Kuglar is suing McGill on behalf of Mishkin.

The university hasn't responded, except for a statement to the media saying there's no evidence linking Mishkin's leukemia with the time he spent in the anatomy building.

Causal link difficult to establish

Dr. Louis Drouin of Montreal Public Health's Occupational and Environmental Health Unit has examined other recent clusters of suspected cancer cases in the province:

• At Montreal's Ste-Justine hospital, 18 lab technicians developed cancer. Public health officials tested air quality and checked for potential hazards in the building. There was no proof of cause and effect.
• In Ste-Hyacinthe, five people at a vocational school developed kidney cancer. Again, no link was established between the cancers and the building's environment.

In "most of these cancer cluster investigations, we cannot have any resolution of the problem," said Drouin.

A 22-year study of cancer cluster investigations by the U.S. Centers for Disease Control found no causal links. Drouin said the Canadian experience is the same.

"When you have two or three people in a small building or a school or a hospital and try to link with a specific occupational exposure which has been 22 years ago, the number is so small," said Drouin. "It can be by chance, it can be real but with the statistical tools we have they cannot conclude."

It will take months – if not years – to establish whether Mishkin lost his life as a result of the dangers in the the place he once worked.