The explosion shook buildings and set off car alarms up to 25 km from the plant and generated a massive column of smoke that stretched high into the sky.

As firefighters rushed to the scene, police cordoned off the area.

Enaex said in a statement that the blast took place at 4:45 p.m. and was caused by an incident in a storage warehouse for products used in the manufacture of dynamite. One person suffered minor injuries, it said.

"As soon as the accident happened, the company's internal emergency protocols were activated and the corresponding authorities were informed, which also came to the scene," the company said. It added that it had launched an investigation.