CNN article

["Jim Hardeman" <Jim_Hardeman@dnr.state.ga.us>]

Colleagues -



Article appeared on CNN.com today ...



URL = http://www.cnn.com/2004/TRAVEL/07/06/life.radiation.reut/index.html



Jim Hardeman

Jim_Hardeman@dnr.state.ga.us 



================



Air crews look at radiation risk from flying

Tuesday, July 6, 2004 Posted: 12:35 PM EDT (1635 GMT) 



DALLAS, Texas (Reuters) -- Airline crews already have their hands full with concerns about stepped up security, congested airports and tipsy travelers.



One more item to add to that list may be radiation exposure.



The union for pilots at American Airlines is trying to increase awareness among air crews that they are being exposed to enough cosmic radiation to fall into a U.S. government regulated category of radiation workers.



The longer a person travels on a jet, the higher the jet travels and the closer the jet flies to the north or south poles, increase exposure to cosmic radiation, which comes from deep space and the sun. The Earth's atmosphere largely shields us from cosmic radiation, but planes fly where the atmosphere is thin.



"It is clear that there are health risks associated with a career of flying," Federal Aviation Administration researchers wrote in a 2002 report on radiation exposure of air crews.



Some of the routes that had the highest radiation exposure included flights between Tokyo and New York, London and Los Angeles, as well as between Athens and New York, it said.



The exposure levels for air crews fall well within federal guidelines for safe exposure for a healthy adult but the Allied Pilots Association said the radiation exposure could present risks for the fetus of a pregnant woman. A fetus has developing cells that are more likely to be damaged by exposure to radiation than an adult.



"For your average passenger, who flies occasionally, it is not an issue. For air crew members who fly more than 75 hours or more a month, that certainly adds up," said Capt. Joyce May, an American Airlines pilot who is the deputy chairwoman of the APA's Aeromedical Committee.



Higher altitudes, increased risk

The problem has become more acute recently as jets are flying at higher altitudes. The high-altitude flights help to cut down on jet fuel use, but they also increase exposure to cosmic radiation.



May said that total radiation exposure doubles with every 6,500 feet of climate altitude.



"For a jet cruising at 39,000 feet, the total radiation is about 64 times higher than at sea level. If you drop down to 33,000 feet, it is only about 35 times greater than sea level," she said.



May and the union are calling for more thorough training for air crews so that they better understand their exposure risks to radiation. They are asking for better tracking of the radiation exposure of crew members and studies to see if the exposure presents any long-term health risks.



A typical air crew member may experience about 200 millirems to 400 millirems more exposure to ionizing radiation than the general population per year. The pilots and flight attendants working routes over the Pacific or Atlantic Ocean will likely top 500 millirems of radiation exposure.



Galactic cosmic radiation is high energy and penetrates all parts of an aircraft equally, scientists said. It is also ionizing radiation, meaning it can penetrate the human body and disrupt the healthy function of cells.



Radiation workers

The United States does not have any regulations for air crews pertaining to radiation exposure, but several European countries classify air crews as radiation workers and monitor their exposure levels.



There are no definitive studies linking cosmic radiation exposure for air crews with health risks, May said, but she did note one medical study showed that pilots had three to four times the rate of malignant melanoma -- a type of skin cancer -- than the general population.



In order to give some perspective, workers at the Los Alamos Nuclear Laboratory, the birthplace of the atomic bomb, have an annual safety limit of 2,000 millirems of exposure, while the preeminent nuclear research lab tries to limit radiation exposure for a pregnant woman to 500 millirems for the term of her pregnancy.



Other federal agencies have a safe, annual exposure level of 5,000 millirems.



Tom Buhl, a top health physicist at Los Alamos said that while air crews may meet the U.S. minimum standard of radiation workers, he does not think they should be classified as such because they do not face the risk of a large, unexpected dose of radiation. "On an airplane, the radiation field is pretty well known. You have a pretty good understanding of what that radiation is," Buhl said.







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