It’s not who you think.
We’ve had days of headlines about unspecified “radiation” being released from two Japanese nuclear reactors as operators struggle to cool their radioactive cores. People in the area, devastated by earthquake and tsunami, are struggling without power, heat, clean water, sanitation, sufficient food – what does the addition of “radiation” mean?
So far, it has meant people have had the wits scared out of them, and little else.
As is unfortunately usual when the word “radiation” is mentioned, rational discussion of the physical facts is lost in hysteria. The people who are really at risk are the Tokyo Electric Power Co. workers struggling to bring and keep those reactors under control. They are the ones close enough to the radioactive sources to risk a dose that might affect their health, and there’s been precious little mention of them.
Every nation sets different limits for radiation exposure for the public and for workers. That’s the practice for most hazardous materials – the idea is that the public shouldn’t be exposed to the same level of risks as workers, who are paid to take more risk. But most reporting takes that public limit as the line of “safety” – below the limit, no problem; above the limit, instant radiation poisoning.
That of course is not the case. In the U.S., the annual exposure limit for radiation workers, such as nuclear plant employees, is 20 times higher than the public level, and in some circumstances up to 50 times more is allowed. (The vast majority of nuclear plant workers get nowhere near even the lower level, though they all must be continuously monitored.)
The threshold at which any physical symptoms of radiation poisoning have been detected is an exposure of 100 times the annual public limit in an hour – a very different type of exposure. The worker limit is calculated by looking at a lifetime of radiation work – an assumed 40 years – and figuring how much exposure anyone can have each year to minimize the cumulative addition to their lifetime cancer risk. The public limit is set by a decision to keep any public exposure basically the same as you or I can get if we move from Washington, DC to Denver, CO, where natural radiation is higher (with no known effects on health).
Radiation exposure, like sun tanning, depends on both time and the intensity of the source. Exposing your skin five minutes in the sun on December 25 and two hours on July 25 are extremely different exposures – but if the reporting from Japan were talking about sunburn, it would be reporting those as the same thing. They aren’t – nor are the real radiation risks today. It’s Japan’s nuclear plant workers who up close and personal with radiation. They are risking their health to keep those plants from truly endangering the public.