CHENNAI- A boiler blast on Wednesday at lignite miner and electricity generator NLC India's plant in the southern Tamil Nadu state has killed six people, the company said, the second deadly accident at the plant in two months.

"Six workmen belonging to a contractor succumbed to injuries on the spot," state-run NLC, which employs more than 12,000 people, said in a statement.

The incident occurred at unit V of the Thermal Power Station-II (TPS-II), the company said, adding that the unit was under shutdown at the time.

"While it was under shut down and maintenance activities continued, a fire broke out in the boiler area subsequent to an explosion," NLC said.

An accident at the same power station on May 7 killed five people and injured three.

More than three people die and over 46 are injured each day in industrial accidents in India, according to government data for the three years ending 2016.

Tamil Nadu, where the NLC India plant is located, is the third most dangerous state in the country to be a worker, the data showed, behind heavily industrialised Maharashtra and Gujarat.

The explosion on Wednesday also injured 17 people, sixteen of whom were sent to a private hospital in the state capital of Chennai for treatment, while the other is being treated at a local hospital in Neyveli, the statement read.

NLC said all four operational 210 MW units of TPS-II had been ordered to shut down for an immediate safety audit and the unit head of the plant had been suspended pending an enquiry.

An independent committee and an internal enquiry committee have been set up to investigate the accident.

(Reporting by Sudarshan Varadhan; editing by Jason Neely, Louise Heavens, Kirsten Donovan) ((Sudarshan.Varadhan@thomsonreuters.com; +919810393152; Twitter: https://twitter.com/sudvaradhan @sudvaradhan;))