After Japan's earthquake and tsunami led to a second nuclear reactor explosion, tests showed low levels of radioactivity on 17 U.S. Navy helicopter crew members after they returned to the U.S.S. Ronald Reagan.
"They probably had particle radiation from the plume that's coming from the reactors and typically by movement that going away moving the aircraft through the air will move the large particles," says Bill Caton from the Marine Corps Logistics Base who is an expert in explosive matter.
He says there are two types of radioactive material, and the crew members in Japan were exposed to radioactive particles (alpha and beta) which resemble dust.
Experts say immediate effects of radiation exposure can include vomiting and headaches.
The simple cleaning measure for this may come as a surprise: "The best way to do it is hot water and soap," says Caton. The 17 U.S. Navy helicopter crew members were cleaned in this manner.
The U.S. Navy and Military is doing what they learned to do from the very beginning regarding radioactive contamination: Caton says they learn how to handle radiation exposure in basic training.
"Even through boot camp everyone goes through the basic N.B.C. -- or nuclear biological chemical â" training," says Caton. "Basically the marines are outfitted with equipment, masks and personal protective equipment to wear if they come in contact with that area."
The nuclear incident in Japan is causing some Americans to become concerned with nuclear plants in the United States.
"They should not be; there are a lot of regulations and standards and safety precautions built into it," says Caton. "Power coming from something is always going to have some inherent risk or danger to it, but it's probably one of the most efficient ways to produce power and relieve ourselves from hydrocarbons is nuclear power and hydro power."
The White House held a press conference saying there is very little danger of radiation reaching the United States.
"Based on the type of reactor design and the nature of the accident, we see a very low likelihood, very low probability that there's any possibility of harmful radiation levels in the United States, or in Hawaii, or in any other US territories," says Nuclear Regulatory Commission Chairman Greg Jaczko.