Chemical manufacturers must immediately comply with the Chemical Disaster Rule, a set of requirements aimed at keeping communities safe from toxic disasters, following a federal court ruling on Friday which called the Trump administration's delay of the rule "arbitrary" and illegal.

"This is a victory first and foremost for the neighborhoods most susceptible to dangerous and toxic chemical releases. Families who live under the shadows of chemical facilities deserve safer practices to prevent future disasters," said Andrew Rosenberg, director of the Center for Science and Democracy at the Union of Concerned Scientists.

JUST IN: In another big court loss for EPA, D.C. Circuit throws out rule delaying Obama-era safety standards for chemical facilities — Amanda Reilly (@apeterka) August 17, 2018

Reading through the opinion, and D.C. Circuit does not mince words: EPA "makes a mockery of the statute." — Amanda Reilly (@apeterka) August 17, 2018

President Donald Trump delayed implementation of the rule, which had been developed by the Obama administration, when he entered office. The regulations required the chemical industry to coordinate with emergency responders ahead of a likely emergency, to maintain transparency with their surrounding communities regarding possible chemical threats, to fully investigate disasters, and to assess whether the use of different technologies by their facilities could prevent chemical emergencies.

The Union of Concerned Scientists noted earlier this year that the delay of the rule likely exacerbated disasters including the Arkema plant explosion outside Houston last August after Hurricane Harvey hit.

"The rule would have begun to prevent and reduce chemical disasters in communities near over 12,500 facilities nationwide if the Trump administration had not abruptly suspended it one year ago, in March 2017," wrote Gretchen Goldman.

The court's decision came "not a moment to soon," for the 177 million Americans who live in places where their safety could be put at grave risk in the event of a chemical emergency, said the climate action group Earthjustice.

"The government cannot withdraw critical safety rules based on political whim—people’s lives should come first," said Gordon Sommers, an attorney with Earthjustice. "The court's order means industry will have to start implementing these critical safety measures immediately—with the new hurricane season underway, there is no time to wait."

Others also applauded the ruling, including some who noted that it was just the latest recent blow to the Trump administration's pro-industry agenda—one that has consistently put the bottom line of the chemical and fossil fuel industries over the safety of Americans.