There are concerns that the rail blockades, which have halted CN freight trains, could have an impact on drinking water.

Cathy Campbell, president of Responsible Distribution Canada, told NEWSTALK 1010's Moore in the Morning that rail is used to transport chlorine, a chemical used in water treatment.

If the blockades continue, she believes some municipalities could be under boil-water advisories within days.

The city of Toronto tells NEWSTALK 1010 its chlorine supply is delivered by truck so it would not feel the impact.

Campbell says chemicals for airplane de-icing would also be affected.

"We certainly don't want to go another week," she says. "That would be seriously critical."

Responsible Distribution Canada is an industry group representing chemical distribution companies.