RIO DE JANEIRO — Prosecutors on Tuesday filed homicide charges against Fabio Schvartsman, the former CEO of the Brazilian mining conglomerate Vale, and 15 other people in the deadly dam collapse last year that killed at least 249 people.

The Minas Gerais state prosecutor’s office said it was bringing homicide and environmental charges against 11 people who worked for Vale and five who worked for the German safety-certification company TUV SUD. The companies will also face environmental charges.

The prosecutor’s office said the charges followed a nearly year-long investigation that concluded the dam posed a critical safety risk since at least 2017, and the situation worsened in 2018. In a statement, prosecutors accused Vale of hiding information related to the safety of the dams “from the government and society, including investors and shareholders of the company.”

They said investigators determined the alleged crimes were carried out in a way “that made it impossible or difficult for the victims to defend themselves — since the dam burst occurred abruptly and violently.”

In a statement, Vale said Tuesday that it would cooperate fully with authorities but “believes the accusations of fraud are perplexing.”

“It is important to note that other authorities are investigating the case and, at this point, it is premature to claim there was conscious assumption of risk to cause a deliberate breach of the dam,” the statement said.

Schvartsman’s lawyers said the charges against him were “hasty and unfair,” and should not have been determined before federal police finish their investigation.

Attorneys Pierpaolo Cruz Bottini, Mauricio Campos and Paulo Freitas said in a statement that Schvartsman took repeated measures to ensure dam safety at Vale, and opened an immediate investigation when the dam burst last year. They said authorities ignored documents submitted for the investigation that show the problems at the dam were not relayed to Schvartsman’s office.

“Those responsible must be held responsible for their actions,” the lawyers said. “But the attempt to punish those who, since the first hour, fulfilled their duty and stood by the authorities to investigate what happened and repair the damage, is unjust and regrettable.”

Vale and TUV SUD have faced scrutiny since the 280-foot tailings dam in the Minas Gerais municipality of Brumadinho collapsed last January, unleashing nearly 2 million cubic meters of toxic waste onto the mine’s offices and a nearby community. Torrents of mud swept away hundreds of people; some are still missing.

Schvartsman has been on leave since March. “Even totally assured of my righteous ways and having fulfilled my duty,” he wrote to company directors at the time, “I request the board to accept my temporary leave in the benefit of the company’s continued operations.”

TUV SUD said Tuesday it is “deeply affected” by the disaster, and “is still very much interested in clarifying the facts of the dam breach and therefore continues to offer its cooperation to the responsible authorities and institutions in Brazil and Germany in the context of the ongoing investigations.”

The company declined to offer further details Tuesday, citing “ongoing legal and official proceedings.”

Waste from the collapse on Jan. 25, 2019, blanketed miles of vegetation. Firefighters uncovered a bus carrying employees in the wreckage. All on board were dead.

Iara Murta, 58, fled her home with her two sisters. Speaking to The Washington Post in the aftermath, she said saw bodies and livestock stuck in the river of mud and mining runoff.

“It’s like watching the worst horror film,” she said.

In July, a Brazilian judge ordered Vale to cover all costs related to the dam’s collapse. Vale, based in Rio de Janeiro, said it would pay families more than $100 million.

Brazilian police announced their first criminal charges against employees of the companies in September. Seven Vale and six TUV SUD employees were accused of falsely claiming the dam was safe just months before it collapsed. If found guilty of criminal misrepresentation, they could face up to 18 years in prison.

Last year’s dam collapse shed light on the dangers of tailings dams, prompting reviews of other locations in Brazil where dams could be at risk for similar types of collapse.

A different Vale-operated dam burst in Minas Gerais in 2015, killing 19 people and displacing hundreds. After last year’s collapse, former environmental minister Marina Silva tweeted that “History is repeating itself,” and that “the government and the mining companies have learned nothing.”