Q&A: Amount of radiation emitted by airport body scanners uncertain

The imaging machine at LAX can see through clothing to search for banned carryon items.

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The imaging machine at LAX can see through clothing to search for banned carryon items.

Scanners' danger unclear

How much radiation does a full body scan at Tampa International Airport emit? Considering every trip, is it too much?

Steve Huettel, who covers the airline business for the St. Petersburg Times, recently wrote this answer to the following question about the full-body scanners at Tampa International Airport: Is the amount of radiation I receive safe?

"Scientists have different opinions. The Food and Drug Administration says the amount of radiation is safe: roughly as much as you would get from cosmic rays during four minutes in the air at 30,000 feet.

"But a group of scientists at University of California at San Francisco says that a scanner manufacturer and government officials miscalculated the radiation dose that X-ray scanners deliver to the skin. They recently asked President Barack Obama's science adviser for a more thorough study of the risks of exposing so many people to the airport scanners, National Public Radio reported.

"Not all scanners use X-rays. Millimeter-wave machines, the model deployed at Tampa International, use reflected radio waves to generate an image."

The Transportation Security Administration, which handles security at airports, says the radiation dose is well below the limits specified by the American National Standards Institute. They also pointed out that the energy projected by millimeter-wave technology is 10,000 times less than a cell phone transmission.

Explosives can't seal oil well

Why can't the oil well be sealed using explosives (non-nuclear)?

BP chief operating officer Doug Suttles told reporters that none of the experts the company has consulted believe explosives should be used to stop the flow, the New York Times reported. The paper reported that Suttles said blasting around the well as "not an option we believe we would ever use."

Tony Wood, director of the National Spill Control School at Texas A&M University-Corpus Christi, says one big problem with setting off an explosion could be the huge amounts of methane coming out of the well.

Methane freezes into a slushy substance called methane hydrate at the depth and temperatures it encounters at the well near the ocean floor. But heat from an explosion could turn it back into a gas, Wood said, and that could cause three problems:

The gas could form a bubble that grows to immense size as it rises to the surface, possibly capsizing ships; the gas could asphyxiate people at the surface; and methane gas is flammable, so it could cause an explosion at the surface, he said.

Q&A: Amount of radiation emitted by airport body scanners uncertain 06/21/10 [Last modified: Monday, June 21, 2010 5:15pm]

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