Low levels of radiation were detected Wednesday in the air filters of a ship moored at the Port of Tacoma, officials told KIRO-TV.
U.S. Coast Guard Lt. Regina Caffrey said the Hyundai Oakland, which last docked in Shanghai, never got closer to Japan than 400 kilometers.
She said radiation has not been detected on any other ships in the Puget Sound and that the “very low levels” have been deemed by several agencies to not be a threat.
There are “no health or safety risks,” Port spokeswoman Tara Mattina told KIRO-TV.
Longshoremen have been cleared to work on the ship in question.