Beijing (CNN) -- Chinese shoppers in Beijing and Shanghai cleared salt from supermarket shelves Thursday amid fears of a potential radiation crisis from Japan's Fukushima Daiichi nuclear plant.
Government officials and experts attempted to calm fears by emphasizing that radiation levels in 41 cities across China remain normal.
Staff from multiple branches of the French supermarket chain Carrefour reported that their supplies of salt have been sold out since Thursday morning in Beijing.
A Shanghai branch reported the same.
Small, local and independently-run grocery stores in Beijing told CNN they have also run out of salt supplies for the first time in recent memory.
One customer in the eastern city of Ningbo told the nation's CCTV that she had purchased a five-year supply to placate her family's fears of radiation.
Iodide tablets were also snapped up at many pharmacies in Beijing and Shanghai, according to state-run China Daily.
In an attempt to dispel fears, China's Ministry of Environmental Protection released a chart on its website showing radiation levels in 41 cities across China fell within normal ranges.
The Centers for Disease Control and Prevention advised individuals against taking potassium iodide tablets unless the government and public health officials recommend doing so.
Iodine in iodized salt is ineffective for preventing radiation effects, according to the World Health Organization.
It does not contain an adequate amount of the iodine necessary to prevent radioactive iodine from damaging the human thyroid gland. It would take 80 tablespoons of salt to make up one prophylactic, or preventative, iodide tablet.
Medical experts in Beijing say that radiation fears at this time are unfounded.
"Right now here in China there is no reason to panic," said oncologist Dr. Philip Brooks of Beijing United Family Hospital.
"Outside the immediate radiation area of the nuclear facility in Japan, the first thing is to stay calm and to realize there has been no significant exposure or expected exposure in the immediate vicinity now."
Brooks said there is no need to take precaution, and if the situation changes, the public will be notified.
"There is no medicine to be taking, they should not be taking potassium iodide," he said. "They should be just learning the facts."
Salt sold in China is largely iodized in step with a national policy to prevent iodine deficiency disorders.
The nation's major salt supplier, the China National Salt Industry Corp., assured a worried public that there are rich salt reserves to meet demand in the country and hoarding salt is unnecessary, Xinhua news agency said.