A search was ongoing for nine people who remain missing, occupants of eight vehicles that had been traversing the Juscelino Kubitschek de Oliveira bridge when it collapsed last Sunday. The structure is the main link between Brazil's Tocantins and Maranhao states.
There were fears the Tocantins River could have been contaminated with sulfuric acid being transported by two trucks that tumbled into the water. A third truck was carrying pesticides.
The danger from those chemicals slowed rescue and body-recovery operations for days while water analyses and inspections of the trucks' chemical tank trailers were carried out.
"The tanks are intact. We are currently working on strategies to remove these products," the spokesman for the Tocantins fire service said.
A local government environment official, Caco Graca, told TV Globo that "the risk of pollution and impact on the environment" was "low."
"The worst-case scenario would have been that the (acid) load spread during the fall. But that didn't happen. The tanks are intact," he said.
The causes of the collapse were being investigated, but officials said initial indications were that the central beam of the bridge -- built in the 1960s -- gave way.
