The incident occurred on Tuesday in the city of Itapecerica da Serra, at a depot belonging to Multiteiner, a company that sells and leases containers to businesses that export goods.

About 64 employees were in a meeting at the depot when a platform collapsed, according to fire department spokesperson Luciana Soares, who added that rescue workers were sifting through the rubble to help the victims.

The incident took place as two candidates for deputy seats, Jones Donizette and Ely Santos, were visiting the facility on a campaign trail in the lead-up to the October 2 elections.

"As they were saying goodbye to the workers, part of the concrete structure broke and they were trapped in the rubble," a press team for the candidates posted on social media.