Brazilian authorities are investigating after a bridge collapsed Sunday, killing at least four people and sending trucks loaded with sulfuric acid and pesticides plunging into a river, raising concerns about water contamination.

A bridge linking two northern states in Brazil collapsed, sending cars and trucks plunging into the river below. A sulphuric acid spill is complicating the rescue operation.

A bridge connecting two states in Brazil's northern and northeastern regions collapsed on Sunday (December 22) as vehicles were crossing. Rescue divers had to await confirmation from scientists that the water was safe to enter before embarking on search missions,