Sent_en: 2zh The initial investigation concluded the disaster to have been a dust explosion that ignited under the silos, but investigators from the U.S. Chemical Safety Board (CSB) and the Occupational Health and Safety Administration (OSHA) have been hampered as OSHA declared them to be unsafe after the accident.
Sent_yy: 最初的调查得出的结论是，这场灾难是一场在筒仓下点燃的粉尘爆炸，但是来自美国化学安全委员会（CSB）和职业健康与安全管理局（OSHA）的调查人员受到了阻碍，因为OSHA在事故发生后宣布这些筒仓并不安全。