A massive blaze swept through a fireworks factory in southern India on Wednesday, killing at least 40 workers and injuring 60 others, police said. The fire spread to 40 of the 60 rooms at the factory, one of the biggest in Sivakasi town in Tamil Nadu state, police officer P Karupaiah said. Witnesses said flames were billowing out of the Om Siva Shakti fireworks factory. News reports said the fire was partly under control more than three hours after it started about noon. The Press Trust of India news agency said about 300 people were working in the factory. Television reports said rescue workers would not be able to account for all of them until the blaze is completely out. Large amounts of firecrackers and raw materials were stored in the factory with major Hindu festivals weeks away. The cause of the fire was not immediately known, Karupaiah said. Sivakasi is about 500 kilometres southwest of Chennai, the state capital. The region has many factories making fireworks, which are used in religious festivals and weddings across India. They also are exported to other Asian countries. Some illegal fireworks factories operate in homes.