The death toll from Monday's massive explosion and fire at a pharmaceutical factory in India’s southern state of Telangana has risen to at least 36 while about three dozen are injured, authorities said on Tuesday.

The fire department recovered the charred bodies of 34 workers from the accident site in an industrial area about 50 kilometres (31 miles) from the state capital Hyderabad, the state’s fire services director GV Narayana Rao told The Associated Press.

Two other workers succumbed to burns and were pronounced dead in hospital, Rao said, adding that debris of the gutted pharmaceutical unit of Sigachi Industries was still being removed to find out if any more workers were trapped.

Nearly three dozen injured workers were admitted to hospitals, he said.

“The whole structure of the factory has collapsed. Fire has been doused, and we hope to finish removing the debris in the next few hours,” Rao said.

Sigachi Industries did not disclose what led to the explosion and fire, but said the plant’s core manufacturing infrastructure was damaged and facility operations would be halted for 90 days. The plant produces microcrystalline cellulose, a chemical compound commonly used in making drugs, the company said.