A bridge collapsed in northern Brazil over the weekend, sending trucks carrying thousands of liters of pesticides and sulfuric acid into the river below, raising fears the water could be contaminated.

The central span of the bridge connecting the states of Tocantins and Maranhão collapsed on Sunday afternoon, killing four people and leaving more than a dozen missing.

It was unclear whether or how much chemicals leaked from the container, but diving operations in the river have been halted while the situation is assessed.

Dramatic video captured by a local councilor who went to the bridge to draw attention to the cracks in the bridge showed the beginning of the collapse.

Councilor Elias Junior said he never expected the bridge to actually collapse while he was there and was “shocked.”

Eight vehicles fell into the river, including three trucks carrying chemicals.

People on both sides of the river in the cities of Estretto and Agianopolis were told not to take water from the river.

Rescue operations are underway on board the ship. The fire department said four bodies had been recovered, including the female driver of a truck and an 11-year-old girl. A man was rescued from the water on Sunday.

The Juscelino Kubitschek de Oliveira Bridge is more than half a kilometer (1,600 feet) long and was built in the 1960s as the main bridge connecting the two countries across the Tocantins River.