Staff at the Prairie Island nuclear power plant are looking for six tools containing radioactive material that have been reported missing.
Xcel Energy says the tools contain sealed radioactive materials, with significantly less radioactivity than what's found in residential smoke detectors.
They were discovered to be missing during an inventory taken in December. Xcel says the situation does not pose any safety threat to plant workers, the public, or the environment.
The company reported the missing items to the Nuclear Regulatory Commission. Xcel is under increased scrutiny from the NRC because the federal agency says there's been a pattern of human error at Prairie Island.
The agency is meeting with Xcel officials next month to discuss the utility's progress in responding to the concerns.