The National Institute of Standards and Technology (NIST) laboratory in Gaithersburg, Md., is undergoing a special inspection by the Nuclear Regulatory Commission after a worker may have been exposed to nuclear contamination.

A five-member NRC team began its inspection on Sept. 26 after a glass ampule containing americium-241 —a radioactive substance — broke in the lab on Aug. 18. A worker was potentially exposed to radioactive contamination, as were a storage area and lab surfaces. A NIST spokeswoman says the employee was treated at a local hospital and released, and “received appropriate medical attention” based on guidance from radiation exposure care specialists.

Testing indicated that the employee may have received a dose of radiation that exceeded NRC annual occupational limits. The employee is undergoing additional testing so that the actual dose can be determined, and a report will be issued within 45 days following completion of the review.

An NRC spokesman stated that, while the employee should not expect to see any immediate health effects, the chances for developing cancer during their lifetime “marginally increases” as a result of the nuclear exposure.

The NRC said that its inspectors have been gathering information related to the event since it was reported to the agency on Aug. 19. Two NRC inspectors were sent to the facility on Sept. 13.