British Columbians spooked by their westerly proximity to ongoing explosions at Japan's quake-damaged nuclear plants are making a run on pharmacies, hoping to boost immunity to any potential radiation drift.

But the provincial government, health officials and pharmacists themselves are encouraging people to stand down from stockpiling potassium iodide, saying no health risks exist.

"There is definitely a panic," said pharmacist Cristina Alarcon, at Hollyburn Medicine Centre in West Vancouver.

"If we had a similar situation here it may be advisable, but in this case, how big is the ocean? I think it's a little bit ridiculous."

Medical authorities have used potassium iodide -- the compound KI -- in radioactive iodine-contamination emergencies before, such as nuclear accidents, to block any uptake by the thyroid.

But that's not necessary here, say officials.

B.C.'s Health Officer Dr. Perry Kendall issued a notice Monday saying it would take five to six days for winds to carry nuclear particles across the Pacific, and by that time any radiation would have dispersed into the atmosphere.

"The consumption of iodide tablets is not a necessary precaution as there is no current risk of radiological I131 exposure," Kendall said in the release.

"Even if radiation from Japan ever made it to British Columbia, our prediction based on current information is that it would not pose any significant health risk."

On Sunday, the B.C. minister for public safety also sent out a statement declaring the public need not fear exposure.

Yet at the pharmacy where Alarcon works, people started making purchases in the form of purple-coloured liquid starting on Saturday, while a colleague at a Vancouver pharmacy told her they've run out of stock having received a dozen requests on Monday alone.

"They were calm but just wanting to protect themselves," Alarcon said, noting pharmacies have also been contacted by the health ministry advising them there is unwarranted alarm around the situation.

If taken improperly, the compound could be a risk in itself, Alarcon added.

Health Canada, the B.C. Centre for Disease Control and international authorities continue to monitor events in Japan.

By Monday night, Japanese officials said radiation was spewing from the crippled Fukushima Dai-ichi nuclear plant in country's northeast.

The development prompted the Japanese government to tell people within 30 kilometres of the plant to stay indoors to avoid exposure as levels were considered high enough to harm human health.

Tens of thousands of people have been evacuated from around the nuclear plant which is the area where any leaks would have their main impact, said the B.C. ministry of health.

"In the event that there is a significant release of radioactive iodine 131, the main impact would be on populations within the vicinity of the reactor in Japan," the ministry said.

Japanese police updated the official death toll from the twin disasters of a magnitude-9 earthquake and tsunami to more than 2,400 people dead early Tuesday, with thousands more still missing.