Stores that sell iodine supplements are selling out as people react to the possibility of radiation exposure from leaks at nuclear plants in Japan.

Prime Minister Harper is trying to reassure Canadians that there is nothing to fear from Japans' growing nuclear crisis.

Harper insists winds will not blow a radioactive cloud to Canadian shores.

"I have been in very regular contact with all senior officials and departments responsible for monitoring this and there is no evidence of a scenario that presents any risk to this country," said Harper.

A Calgary health food store is one of many across the country that is sold out of iodine supplements.

Despite the Prime Minister's assurance that there is no risk, Canadians aren't taking any chances.

They are buying up iodine in the belief that it will protect them from possible radiation exposure.

Stores in B.C. were the first to report iodine shortages as fear spread.

Potassium iodide is a specific formulation of iodine that is sold over the counter and is effective to treat the thyroid from radiation exposure.

Iodine supplements are not effective for this type of treatment and are not necessary as most people get enough in their diet.