An explosion at an illegal workshop in eastern China has killed 13 people.

The official Xinhua News Agency said Monday another 14 people were hurt in Sunday's blast in Wenzhou city in Zhejiang province.

It said the family-run workshop, which made locks, was illegal. The blast happened when sparks from a polishing machine ignited dust in the workshop.

Industrial safety is a problem in China, with safety rules standards widely ignored and many small factories operating without proper safety equipment.