The prime minister is celebrating St-Jean-Baptiste Day in the heart of the asbestos industry as Canada's delegation to an international summit draws ire by keeping the carcinogen off a hazardous-chemicals list.

Stephen Harper is visiting Thetford Mines, Que., Friday with Industry Minister Christian Paradis, the MP for the riding. Thetford Mines is home to the country's last operating asbestos-mining operations.

Harper's Conservative government steadfastly refuses to let asbestos be added to a United Nations treaty called the Rotterdam Convention.

Listing asbestos on Annex III of the convention would force exporters such as Canada to warn recipient countries of any health hazards.

Those countries could then refuse asbestos imports if they didn't think they could handle the product safely.

Canada has twice before played a lead role in blocking the inclusion of asbestos under the Rotterdam Convention, which operates by consensus, and the country is doing so again at this week's summit.

The earth negotiations bulletin published by the International Institute for Sustainable Development reports other countries are "dumbstruck" by Canada's reasons for blocking the listing.