Investigation of an Accidental Radiological Release in an Underground Disposal Facility.

A radioactive release took place at the Waste Isolation Pilot Plant near Carlsbad, New Mexico, on 14 February 2014. An alarm from a Continuous Air Monitor caused a switch from unfiltered to filtered air exiting the facility through High-Efficiency Particulate Arrestance filters. The activity measured on the filters demonstrated first order decay, indicating that the release was a single release. The facility was reentered in April 2014 and photographic evidence pointed to a single breached 55-gallon drum that originated at Los Alamos as the source of the release. Data were collected and analyzed to verify the source and cause of the release.