Thirteen labourers were injured when scaffolding collapsed in Uttar Pradesh's Sonbhadra district in the early hours of Sunday, the company which had employed them for maintenance work said.

In a letter addressed to the district magistrate and Superintendent of Police of Sonbhadra, factory manager of Lanco Anpara Power Ltd SK Dwivedi said the accident took place around 2.45 am when the iron structure fell during maintenance work.

While eight laborers were discharged after treatment, another five are in a serious condition and have been admitted to a government hospital, he said.

Of the five laborers, three got head injuries, one suffered a broken hand and another fractured his leg, Dwivedi said, adding, ''All are out of danger''.

Dismissing reports in a section of the media about a boiler blast at the plant,

Dwivedi told PTI, ''The unit was closed for maintenance since March 22, and the maintenance work is of around one-month duration. The scaffolding on which the laborers were working suddenly came down. Luckily, there were no laborers standing below them, and they were wearing a helmet.'' Dwivedi also said that an internal inquiry of the company will be conducted to ascertain the reasons behind the accident.

Uttar Pradesh Chief Minister Yogi Adityanath has taken cognizance of the incident and directed the Additional Chief Secretary (Energy) to probe the matter. Adityanath also said the probe should fix the responsibility for the incident, and effective action should be taken at the earliest. He also directed the local administration to ensure that the injured get adequate treatment.