A Seattle Fire Department hazmat team secured the area near Harborview Medical Center at Terry Avenue and Terrace Street on First Hill.
There is no threat to the public from the radioactive material, which was being transported from UW Medicine’s Harborview Medical Center Research and Training Building, said Seattle Fire Department spokeswoman Kristin Tinsley.
Harborview spokeswoman Susan Gregg said 10 people who were exposed were taken to Harborview’s emergency room Friday morning. All were in satisfactory condition and have been discharged.
The investigation of the incident is being handled by the state Department of Health, which had two inspectors on site for the removal of a device called an irraditor, which contains cesium-137, a radioactive material, said DOH spokeswoman Kristen Maki.
Maki said the irradiator was being transferred to a safe disposal site when a leak in the device was detected.
Gregg said the removal of the radioactive material was part of a nationwide federal program decommissioning devices called irradiators, which are used to expose a range of samples to gamma radiation for purposes such as sterilizing medical supplies and studying the effects of radiation.
In a statement, the Department of Health said while this type of work is fairly common, the release of radioactive material is “very rare.”
Those exposed include the two state inspectors, contract workers tasked with removing the device and law enforcement officers who were observing the removal, according to the statement. A few of the people contaminated are Harborview employees, Gregg said.
No firefighters tested positive for exposure, Tinsley said.
Correction: A photograph was removed from an earlier version of this story because a building where the radiation breach happened was misidentified by the Seattle Fire Department.