We believe there were three explosions while workers were welding or using electricity. We can say the blaze was started by inflammable gases in the basement.

• 连续的爆炸将室内灭火设施全部摧毁。由于空间封闭，地下室内的温度仍然很高，加上有毒浓烟弥漫，导致救援工作进展缓慢。