11 April 2017, 03:45 GMT
Descending onto NIST's headquarters in Gaithersburg, Maryland, the five-member team began the inspection this week after reports that a "glass ampule broke" in one of the labs back in August.
According to a September 20 statement from NIST, the employee discovered the contamination August 18 in a lab used to prepare radioactive samples. The ampule had broken inside a "lead-lined container inside of a larger protective storage box."
Initial tests first indicated that the employee was exposed to a dose of radiation above the NRC's annual occupational limits; however, additional testing is being conducted to determine the actual dose, officials told AP.
The final results will be included in a report expected within the next 45 days. The NRC team is currently investigating the events leading up to the incident and NIST's corrective actions.
