NANJING, July 29 (Xinhua) -- The death toll in a powerful explosion at a factory in the eastern Chinese city of Nanjing Wednesday has risen to 13 after three more bodies were found under the debris, local authorities said Thursday.
The explosion ripped through an abandoned plastics factory in northern Nanjing's Qixia District at 10:11 a.m. Wednesday, leaving buildings within a radium of 100 meters of the explosion site serious damaged. A bus near the site was also destroyed by the ensuing fire.
The fire triggered by the explosion was put out early Thursday and rescuers found three more bodies when clearing the debris, the rescue headquarters said in a statement.
A total of 120 injured people, including 14 in critical condition, are in hospital. Of the 14 seriously injured, three were out of danger after emergency treatment, it said.
Police have arrested four people, including three construction contractors and one official at the Nanjing No. 4 Plastics Factory responsible for the safety of the dismantling work.
The blast was caused by a gas leak after a propylene pipeline was damaged when workers were using excavators to retrieve garbage, such as copper pipes, that could be sold after the dismantling work was completed, the rescue headquarters said.
The gas leak started at 9:56 a.m. and explosion occurred at 10:11 a.m.Wednesday. Gas supplies were cut off a minute later, said Liu Zhaohua, deputy head of Nanjing's work safety bureau.
Local environmental authorities have set up eight monitoring sites to check air and water quality within a radius of 10 km of the site.
The latest monitoring results found no pollution following the explosion. But local authorities will continue to monitor air and water quality for some time.
Power, water and gas supplies to thousands of households living near the site have resumed.