For months the Navy nuclear-powered submarine USS Houston has been leaking radioactivity into the water as it traveled to ports in Guam, Japan and Hawaii. The leak was discovered during a routine maintenance check last month.
The Navy is saying that the amount of radiation that leaked with almost undetectable. Japan has been alerted though because the sub was docked in their water for a time.
The discovery happened when a build-up of leaking water popped a covered valve while in dry dock. A sailor on the site had his leg covered in the water when it popped. The sailor has tested negative for radiation contamination.
When the leak started is not known.
This comes on the heels of thousands of Japanese protesting the pending arrival of the USS George Washington into their waters. The George Washington is a nuclear-powered ship that is replacing the USS Kitty Hawk.
A fire broke out on the George Washington in May when crew members were smoking near flammable materials that had been improperly stored.
The nuclear reactor was not damaged during the fire but the ship returned to San Diego, California for repairs.
The ship is due to arrive in Japan at the end of September.