SAO PAULO (AP) — A bridge linking two northern states in Brazil collapsed, killing at least two people and leaving a dozen others missing, police said Monday. A sulphuric acid spill is complicating the rescue operation.

Footage obtained by local residents showed cars and trucks were crossing the Juscelino Kubitschek de Oliveira bridge when large sections crumbled into a river on Sunday.

Police operating on the border of the northern states of Maranhao and Tocantins said that eight vehicles were missing: four trucks, two cars and two motorcycles. Police and Brazil’s road department said they started investigations on the case.

The 533-meter-long (1,748-foot-long) bridge between the cities of Estreito and Aguiarnopolis was built in the 1960s and located 1,300 kilometers (800 miles) north of the capital, Brasilia.

Magnum Coelho, a colonel at the local firefighters’ office, told journalists that sending divers for rescue operations is dangerous because the Tocantins River could be contaminated by sulfuric acid from one of the missing trucks that fell from the bridge.

The bridge collapse was among several tragedies in Brazil over the weekend. On Saturday, a crash involving a passenger bus and a truck killed dozens of people on a highway in Minas Gerais, a state in southeastern Brazil. On Sunday night, authorities confirmed the number of deaths had risen to 41.

Local authorities said Sunday that the truck driver is on the loose and could face criminal responsibility because of allegedly overweight cargo that may have caused the crash.

The Minas Gerais state’s fire department said that several people were taken to hospitals near the city of Teofilo Otoni. The bus had reportedly departed from Sao Paulo and was carrying 45 passengers.

Also on Sunday, at least 10 people died after a small plane crashed in Gramado, a southern town popular with tourists. More than a dozen people were injured on the ground, Brazil’s Civil Defense Agency said.

The plane was piloted by Luiz Claudio Galeazzi, a Brazilian businessman who was traveling with his family to Sao Paulo State. Brazil’s Civil Defense Agency said that the plane hit the chimney of a home and then the second floor of a building before crashing into a cellphone store.