The blast occurred at the C.Vale co-operative in the small town of Palotina, about 600km from the state’s capital Curitiba. Parana is one of Brazil’s top grain-producing states.

Experts say grain dust particles are highly combustible and can cause fires or explosions. The particles can be from wheat, oats, barley, or other types of grain that form layers or become airborne in an enclosed space.

For a grain dust explosion to occur, they say that four elements have to be present: fuel, oxygen, confinement, and a source of ignition.

C.Vale did not immediately respond to questions about the circumstances of the incident or explain what the stored product was that exploded.

C.Vale, which stores grains in 125 units across five Brazilian states and in Paraguay, said in a separate statement that rescue workers were still scouring the rubble in search of the missing person today.

It noted that nearly a dozen people had been hospitalised, excluding the fatalities.

“I’m deeply saddened by what happened at C.Vale,” agriculture minister Carlos Favaro wrote on messaging platform X, formerly known as Twitter. “I express my condolences to the families of the victims.”

Acting Parana governor Darci Piana headed to Palotina, a city of some 35,000 people, alongside state secretaries to follow the rescue operations and provide support to the families, the government said.