NEW DELHI (AP) — Several explosions at a private fireworks factory in southern India killed at least 15 workers and injured 26 others on Friday, police said.

Those injured in the blasts at the factory in Tamil Nadu state’s Virudhunagar district were taken to a nearby hospital for treatment, police officer Raj Narayanan said.

Ten fire engines were called to fight the fire, which destroyed four sheds at the factory.

Narayanan said 11 people died on the spot and four later succumbed to burn injuries in the hospital. Four workers were allowed to go home after receiving first aid.

The explosions occurred while chemicals were being mixed by the workers to make fireworks, the Press Trust of India news agency said.

Fireworks manufacturing is a big business in India, where fireworks are often set off at festivals and weddings.

Many illegal factories produce fireworks that are cheaper to buy than legally made ones.

The area where the blast occurred is 520 kilometers (325 miles) south of Chennai, the state capital.