On May 30, 2019, a JIT was appointed to perform an investigation to identify Lessons Learned from the May 2, 2019 breach of a cesium-137 sealed source and resultant spread of contamination at the University of Washington (UW) Harborview Research and Training Facility (HRT). This was a joint investigation involving NNSA employees and Triad National Security, LLC (Triad) employees (as the Management and Operating [M&O] contractor, or simply the M&O). The Team’s responsibilities have been completed with respect to this investigation. The analysis and identification of the contributing causes (CCs), the root cause (RC), and the Judgments of Need (JONs) resulting from this investigation were consistent with methodology discussed in the Department of Energy (DOE) Order 225.1B, Accident Investigations, dated March 4, 2011.