Frozen blood stem cells could save workers' lives if they become ill after exposure to high levels of radiation

Japanese authorities are considering plans to collect and freeze cells from engineers and water cannon operators at the Fukushima nuclear power plant in case they are exposed to dangerous levels of radiation.

The proposal has been drawn up as a precautionary measure that could potentially save the lives of workers if they receive high doses of radiation while battling to bring the damaged nuclear reactors under control.

High levels of radiation can cause serious illness and death from bone marrow failure, but the condition can be treated if patients are seen quickly enough and given transplants of blood stem cells collected before they are exposed.

The procedure requires workers to take a drug for several days that causes their bone marrow to release stem cells into the blood. They are then hooked up to a machine through which their blood is passed and filtered to extract the stem cells.

The procedure is already used to treat cancer patients whose bone marrow is destroyed by chemo- or radiotherapy.

Alejandro Madrigal, scientific director at the Anthony Nolan transplant charity and president of the European group for blood and marrow transplantation, said the plan made sense given the risk to workers at Fukushima. He said more than 50 hospitals in Europe have agreed to help the Japanese if required.

But Robert Peter Gale, a US medical researcher advising the Japanese government, said the move might cause more problems than it solves. "It would be nifty if you could do it, but you are dealing with 800 workers and you might need these cells for only a small percentage of them."

Another downside is that workers who have had their bone marrow cells stored might become cavalier and take unnecessary risks, Gale said. "These cells can reconstitute bone marrow function; that is not the only target of high dose radiation, they would have damage elsewhere, to their lungs, gastrointenstinal tract and their skin. I, and a number of colleagues, feel it's not an appropriate thing to do."