Lucknow: NTPC has suspended a general manager at its Unchahar plant without specifying his role in Wednesday's explosion of a boiler ash pipe that has claimed 32 workers' lives so far.

R.K. Sinha, group general manager at the utility, had on Thursday night said the cause of the tragedy was "not human error but mechanical error".

An NTPC official said a two-letter suspension letter was handed to Malay Mukherjee, general manager (operations and maintenance), on Friday after a meeting of senior officials in Delhi.

At a news conference in Delhi, NTPC chairman and managing director Gurdeep Singh denied that the plant's sixth unit, where the accident occurred, had been commissioned "prematurely", as alleged by local Samajwadi Party MLA Manoj Pandey.

But plant sources alleged that a senior state labour department official had issued a no-objection certificate to the unit's boiler in April without a physical verification.

"The same official had been arrested in February on the charge of demanding a Rs 1-lakh bribe from an Agra-based company for issuing a no-objection certificate. But once he received bail after a month, he was allowed to rejoin his post," an official from the Unchahar plant told this newspaper.

Surprisingly, state BJP spokesperson Harish Chandra Srivastava too echoed Pandey's allegation on Friday, saying the sixth unit had been made operational six months before it was ready. "Those responsible should be arrested for risking workers' lives," he said.

Such a claim appears to implicate the central government, which runs NTPC, and state BJP leaders had so far insisted that nothing could be known before a probe handed its report. It wasn't clear whether Srivastava was airing his personal views.

Shailendra Dubey, leader of a state association of power engineers, said: "The plant started production before it was ready because the government (Centre) was eager to claim credit for making it operational in record time."

He added: "Despite knowing since Monday that ash clinker (a stony residue from burnt coal) was forming in the pipe, NTPC continued running the unit. The clinker blocked 10 metres of the ash pipe, causing it to explode."

But Gurdeep, the CMD, claimed that engineers with 28 to 30 years' experience were present at the plant, addressing every problem.

"So we don't want to jump to conclusions without an inquiry report, which will come in a month," he said.

He confirmed the deaths of 32 employees, including an assistant general manager.