[en] Fourteen persons were injured, one fatally, when the ground upon which they were working collapsed, forming a subsidence crater in the recording trailer park of the MIDAS MYTH/MILAGRO nuclear weapons effects test on Rainier Mesa at the US Department of Energy's Nevada Test Site on February 15, 1984. Those persons injured were contractor and laboratory employees from Reynolds Electrical and Engineering Co., Inc. (REECo), Pan American World Services, Inc. (PANAM), and the Los Alamos National Laboratory (LANL). This report presents the results of an investigation into the causes, effects, and response to the accident. 42 figures