The blast occurred on Thursday at the Chenjiagang Industrial Park in the city of Yancheng, in Jiangsu province, and the fire was brought under control on Friday. 

Meng's union has been offering free food and drinking water to those donating blood since the center was set up Thursday.

Gao Shuibao, a volunteer at the local Red Cross society, estimated at least 280 people donated their blood on Thursday and the number stood at more than 200 on Friday morning.

Zhang Yinlong, whose home is about 20 kilometers away from the donation point, had come in for the fourth time on Friday to give blood.

"I came at 5 pm yesterday, but only found an extremely long line. I went back home and came back again at about 8 pm, but had to give it up after waiting for two hours," said the 38-year-old.