© U.S. NavySeventeen crewmembers on three U.S. Navy helicopters were found to have been contaminated with low levels of radiation, officials say.
Seventeen U.S. Navy crew members have been contaminated with low-levels of radiation during disaster relief missions in Japan, military officials said Monday.

The radioactivity was detected when the service members returned to the aircraft carrier Ronald Reagan aboard three helicopters. They were treated with soap and water and their clothes were discarded.

"No further contamination was detected," the military said.

The helicopters were also decontaminated.

The U.S. 7th Fleet, positioned about 100 miles northeast of the Fukushima Daiichi nuclear power plant to deliver aid to Japan's coastal region, moved its ships further away due to "airborne radioactivity" and contamination found on its planes.

The military noted, however, that the level of contamination was very low, and the ship movement was merely a precaution.

"For perspective, the maximum potential radiation dose received by any ship's force personnel aboard the ship when it passed through the area was less than the radiation exposure received from about one month of exposure to natural background radiation from sources such as rocks, soil, and the sun," the Navy said.

The Fukushima nuclear power plant suffered a second explosion Sunday. At least six workers at the plant were injured in the blast, officials said. A smaller explosion rocked the plant on Saturday.

Radioactive steam was vented recently from the plant in order to ease pressure on the reactors and prevent another meltdown, CNN reported. It is believe that a meltdown previously occurred in at least one of the reactors in the last few days.

"We remain totally committed to our mission of providing assistance to the people of Japan," Navy spokesman Jeff Davis told ABC News.