After the blast, some 930 firefighters joined the rescue, and as of 7 am on Friday, fires had been extinguished, officials said.

A total of 3,500 medical staff members, 16 hospitals and 90 ambulances responded. A national-level medical team of specialists in intensive care, burns, trauma, neurosurgery and psychology was rushed to the site, the National Health Commission said.

Nearby primary schools and kindergartens were suspended, and over 3,000 workers and almost 1,000 villagers were evacuated, the rescue headquarters said on Friday morning.

A resident of Wangshang village, about 500 meters from the blast, described moments he said he would never forget. The explosion destroyed windows and doors at his house, "and it even blew the back door through the front wall," said the man, who gave his name as Chen.

His elder sister's husband, who worked at the plant, died in the accident, and his nephew, also presumed to have been there, had not been heard from, Chen said as he packed on Friday to move to his uncle's home in a neighboring city.

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