On December 21, 2018, an Accident Investigation Board was appointed to investigate the December 19, 2018, construction lifting accident at the Los Alamos National Laboratory that resulted in serious injuries to a subcontract employee. This was a joint investigation involving NNSA employees and Triad employees (as the M&O contractor, or simply the M&O). The Board’s responsibilities have been completed with respect to this investigation. The analysis and the identification of the contributing causes, the root cause, and the Judgments of Need resulting from this investigation were performed in accordance with the Department of Energy Order 225.1B, Accident Investigations, dated March 4, 2011.