Thirty-six people have died as the result of an explosion at a coal-fired power plant in northern India.

The explosion on the 1st of November at the Unchahar power plant in the state of Uttar Pradesh initially killed 20 workers and injured around 85 others, according to National Thermal Power Corporation (NTPC), the plant’s owner.

The death toll has now risen to 36, according to the Hindustan Times and other local media reports.

NTPC said that the explosion occurred in the boiler of Unit 6 at Unchahar, which is thought to have been undergoing a test run in preparation for commissioning.

India’s Power Ministry has set up a committee to investigate the blast.