The Japanese Government is handing out iodine pills to prevent the risk of thyroid cancer, as radioactive steam spews from nuclear reactors following a massive earthquake and subsequent explosions at a nuclear power plant.

Fears over health risks rose today as a third explosion took place at Fukushima Daiichi nuclear power plant, increasing the danger of a nuclear meltdown and radiation leaks.

The iodine pills are hoped to flood the thyroid gland with ordinary iodine in hopes of preventing it from taking up the radioactive form, reports AP News.

Several plant workers have become ill due to exposure, but the risk to the public is low, as only small levels of radiation have been released from the plant, officials have said.

However, some 170,000 residents living within a 30km radius of the plant have been urged to stay indoors as a precaution.

The ability of the plant’s containment vessels to hold the melted fuel will determine the level of radioactive fumes that are released.