A cloud of smoke appears after another explosion at the Arkema plant in Crosby, Tex., on Sept. 3, 2017. (John Taggart/For The Washington Post)

In a lawsuit filed after Hurricane Harvey, a federal judge has ordered the Chemical Safety and Hazard Investigation Board to force the disclosure of chemical emissions resulting from accidents.

More than 1,000 industrial chemical accidents take place every year. The biggest include the explosions that killed 15 people at a fertilizer plant in West, Tex., and the explosions that took place at the Arkema chemical plant in the Houston area after unprecedented flooding caused by Hurricane Harvey.

Judge Amit Mehta of the U.S. District Court for the District of Columbia said that the Clean Air Act required the federal agency, known as the Chemical Safety Board, to investigate chemical fires, explosions, leaks and other accidents. But the board has not yet put regulations into place that require disclosure.

Mehta observed that the agency has had more than 20 years — far in excess of any “unreasonable delay” — to promulgate a final regulation and ordered the board to come up with a regulation within 12 months. “The court will not grant it two full years to do what it should have done long ago,” Mehta wrote.

The lawsuit was filed by Public Employees for Environmental Responsibility and other nonprofit environmental groups: Air Alliance Houston, the Louisiana Bucket Brigade, and United Support and Memorial for Workplace Fatalities.

PEER also represented former CSB managing director Daniel Horowitz, who was ousted last summer after being on administrative leave for three years. Horowitz has advocated for a stronger role for the board.

“CSB has been collecting accident data for a while, just haphazardly and without a regulation,” Horowitz said in an email, adding that it would not “add that much workload” for the board. He said that the CSB created reporting forms and a database for the information when he was still managing director there.

Horowitz said that the ruling was “a major victory for community groups seeking better information about industrial chemical accidents. Too often, the public and first responders have been left in the dark about the hazardous chemicals released during plant emergencies.”

Last September, a group of first responders exposed to smoke from a chemical plant fire in Crosby, Tex., after Hurricane Harvey sued the owner of the plant for more than $1 million, saying that they vomited and gasped for air in the middle of the road in a scene the suit described as “nothing less than chaos.”

The responders alleged that the plant owner, Arkema, minimized the dangers of exposure to the fire and failed to warn the responders on the perimeter of the mandatory 1.5-mile evacuation area to move farther away from the fumes after the first of nine trailers full of volatile organic peroxide burst into flames in the early nighttime hours of Aug. 29, 2017.

“Emergency personnel arrived on scene, and even before exiting their vehicle, they became overcome by the fumes as well,” the lawsuit said. “Medical personnel, in their attempts to provide assistance to the officers, became overwhelmed and they too began to vomit and gasp for air.”

Arkema said it regretted that anyone suffered harm, particularly first responders, but added in a statement that it rejected suggestions that it misled anyone or failed to warn of the dangers of breathing smoke from the massive fire.

“Now, all companies will have to report the details of accidents, and those reports will be available to the public from a single reliable source,” Horowitz said.

The CSB has been a controversial agency for many years. It fought with other agencies to get access to the blowout preventer that was one of the causes of the BP oil spill in the Gulf of Mexico in 2010. It tangled with the Environmental Protection Agency’s inspector general over document releases. And later, it was subject to infighting. But the small agency has also been the source of detailed analyses of chemical accidents.

Brady Dennis contributed to this report.