The licence of Om Sakthi Fireworks Industries was cancelled for multiple violations only a day before Black Wednesday, officials said.

Officials of the Department of Explosives, who were present at the site, claimed that the suspension order was issued online to the owner, Murugesan, only on Tuesday. The order was sent by post to the District Collector and the Superintendent of Police.

“During a random inspection on August 28, Deputy Chief Controller of Explosives B. Rengasamy found large-scale violations of safety norms in the unit. The licence was suspended only on September 4,” an official said.

Forty violations

The officials had detected 40 violations, including overstocking of explosives, both raw material and finished goods, and employment of workers in excess of the permitted strength.

As different kinds of explosives with diverse chemical properties were being used, the exact cause or point of the explosion could not be ascertained immediately.

“Further enquiry with the workers is required to come to a conclusion,” the official said.