More than 1,000 companies involved in handling or manufacturing dangerous chemicals in densely populated areas have been ordered to renovate or remove their facilities since 2014, but the process has hastened since the Tianjin explosions which had killed at least 150 people, authorities said. 

"Many provincial governments have filed reports after the blasts in Tianjin, involving the removal and renovation of over 1,000 factories," Miao Wei, head of the Ministry of Industry and Information Technology, said in a conference on Saturday.

The ministry and the State Administration of Work Safety began removing and renovating factories with dangerous chemicals in densely populated urban areas in 2014, Miao said. "Some local authorities failed to faithfully implement [the policies] until the Tianjin blasts."

The removal of the factories will cost an estimated 400 billion yuan ($62 billion), to be shouldered jointly by local governments and companies with supports from the central government, especially in underdeveloped areas in central and western China, said Miao.

Two huge explosions ripped through a warehouse containing hazardous chemicals in Tianjin on August 12.

Chinese law on businesses engaged in dangerous chemicals states that the storage of such materials should be at least 1,000 meters from public buildings and transport networks. But three residential communities were within a kilometer of the deadly explosions.