RIO DE JANEIRO -- A company-commissioned study released Thursday on a deadly dam break in Brazil found that none of the structure's monitoring systems gave warning of the collapse that killed at least 257 people — though other experts have said the disaster could have been prevented.
The report released by the mining giant Vale said that "none of the monitoring devices detected precursors to failure” ahead of the Jan. 25 disaster in the city of Brumadinho.
The collapse killed at least 257 people, with 13 people still missing. It unleashed a torrent of thick reddish-brown mud that destroyed houses, roads and trees and contaminated nearby rivers.
It prompted a wave of criticism of the mining company and of industry regulators. A report released by congressional investigators in October recommended charges against the company and several senior executives, and the case remains under investigation by prosecutors.
The authors of the 81-page Vale-commissioned study also concluded that dam collapses are “rarely due to one cause” and listed several contributing factors, from design and construction of the structure, to water management issues and intense rainfall.
The report states that none of the four experts that co-authored the study had previously worked for Vale or on any matter relating to the dam, though critics questioned its objectivity.
Cannelle Lavite, a legal adviser at the European Center for Constitutional and Human Rights in Germany, said some of the Vale report's findings contradicted previous investigations. She had been part of a separate investigation into the role of a German company that had certified the dam's safety.
The Vale-commissioned report states that there were no "apparent signs of distress prior to failure," a crucial point about the possible responsibility of the firm.
“That is in contradiction with Brazilian prosecutors who found very serious issues of drainage in the year prior to the failure and in the few days before as well,” said Lavite, who traveled to the mining site in Brumadinho. She said parliamentary inquiries had also found that prior signs of possible failures had appeared. “It is clear they don’t want to acknowledge any warning signs,” she said.
After the dam collapse, chief executive officer Fabio Schvartsman and three other senior executives stepped down. Vale said then that its board of directors had accepted their resignations after prosecutors recommended their removal.
The congressional investigation asked for the indictment of Vale, a branch of certifying company TÜV SÜD and 22 individuals including Vale's Schvartsman.
The European Center for Constitutional and Human Rights filed a complaint in Berlin against TÜV SÜD Germany in October, alleging negligent homicide, private bribery and causing a flood by negligence. The prosecutor's office will decide whether to open an investigation.
Vale, one of the world's largest mining companies, hadbeen under the microscope even before the accident. In November 2015, a dam owned by Vale and Australian mining company BHP Billiton also burst, killing 19 people and contaminating a nearby river.
In March, the firm warned that four of its dams in Brazil could collapse at any moment. The company has said it adopted a series of preventive measures to increase safety at its dams. Some of the communities nearby have also been evacuated.