The death toll in Tuesday's chemical plant explosion has climbed to 15, after two seriously injured workers died in hospital, authorities in North China's Hebei province said.

The blast ripped through Hebei Keeperchemical Industries Co, Ltd in Zhaoxian county at around 9:30 am Tuesday. It flattened one of the factory's workshops and shattered window panes within a radius of 2,000 meters, witnesses and local government officials said.

As of Tuesday night, rescuers had retrieved 13 bodies from the ruins. More than 40 people were hospitalized with injures.

Dozens more were feared missing or dead at the scene, according to Zhaoxian county's deputy chief Wu Haijiang.

Wu said about 100 people were at work when the blast happened. p But the emergency rescue headquarters were forced to halt search and rescue Tuesday night, fearing further blasts might cause more fatalities, he said.

Rescue work would resume Wednesday.

The chemical plant was founded in 2005, with an investment of 217 million yuan, the county government's press office said.