JINAN - Four workers were killed and 10 others injured after a workshop collapsed in Shandong province Monday afternoon, local authorities said.

The accident happened around 4:30 pm in a packing workshop of a detergent factory in the city of Liaocheng, according to local government officials.

Of the 14 people injured in the accident, four died in hospital after emergency medical treatment failed.

Initial investigations indicated that an excessive amount of products stored on the roof of the workshop caused the collapse.