一、事故经过 １９９９年７月２８日，宁夏回族自治区银川某化肥厂合成车间安排５号机大修。８时２０分，合成车间检修一班班长姚某将任务布置完后，带领检修工７人和天车工李某、起重工武某来到５号机检修现场开始工作。９时左右，电气车间检修二班也进入５号机现场，参加对５ First, the accident After July 28, 1999, Yinchuan Ningxia Hui Autonomous Region, a fertilizer plant synthesis workshop on the 5th machine overhaul. 8:20, a workshop repair monitor classmate Yao will be arranged after the task, led the overhaul 7 and crane workers Lee, crane Wu came to the maintenance of the scene on the 5th site to work. About 9 o’clock, the electrical workshop maintenance class 2 also entered the scene on the 5th machine to participate in the 5