NEW DELHI (AP) — Police say a blaze in a fireworks factory in central India has killed 15 people and seriously injured another four.

Police officer Kishore Gurjar says the fire started on Saturday while the workers were making firecrackers in the factory near Ujjain in Madhya Pradesh state. It’s about 775 kilometers (480 miles) southwest of New Delhi.

Gurjar said the fire has been doused and all the workers accounted for. The cause of the fire was not immediately known, he said.

India has a huge demand for firecrackers, which are used in religious festivals and weddings. Fires are common in the factories in the absence of proper safety standards.