The company's Crosby, Texas, plant became waterlogged and lost power needed to keep organic peroxide chemicals from igniting after Hurricane Harvey dumped more than 50 inches of rain on the area. The untended chemicals caught fire and burned for days, injuring 21 safety workers and forcing residents from their homes.
Arkema Inc and former plant manager Leslie Comardelle were found not guilty in a directed verdict by Judge Belinda Hill on Thursday. On Wednesday, she dismissed an endangerment charge against Arkema's U.S. chief executive, Richard Rowe, saying prosecutors had not presented enough evidence to support the charge.
Prosecutors last month separately dropped a criminal assault charge against Arkema and former logistics executive Michael Keough over smoke inhalation injuries suffered by public safety workers assigned to guard the plant.
"It is beyond unfortunate that these ill-founded charges created years of undue hardship" for the executives, Arkema spokeswoman Janet Smith said in a statement. She said the company had urged emergency workers wear respirators if they might be exposed to the smoke.
The company had maintained the charges, brought by Harris County officials, were an attempt to criminalize a natural disaster.
"Today's ruling by a judge doesn't change the fact that dangerous chemicals on Arkema property ignited and were belched in a cloud of toxic smoke over the surrounding communities, and a first responder there protecting people is now on a lung-transplant list," said Dane Schiller, a spokesman for the Harris County District Attorney's office.
The trial had resumed last month after being suspended in the spring due to the COVID-19 pandemic. During the trial, Judge Hill sanctioned prosecutors for withholding evidence beneficial to the defense.
(Reporting by Gary McWilliams; Editing by Steve Orlofsky)