A grand jury has indicted a chemical manufacturer and two of its leaders, saying they were responsible for a plant in Texas “recklessly” releasing a toxic cloud during Hurricane Harvey last year, officials said Friday.

The company, Arkema North America, its chief executive, Richard Rowe, and the manager of its plant in Crosby, Tex., Leslie Comardelle, were indicted, according to a statement from Kim Ogg, the district attorney in Harris County.

The indictment charged that they all had a role in the chemical release, which risked serious harm to residents and emergency responders, the statement said. Prosecutors maintain the release was preventable.

Chemicals at the plant had to be kept frozen to avoid bursting into flames, but temperatures increased after floodwaters knocked out power. As a result, the chemicals exploded on Aug. 31 and Sept. 1, 2017.