Federal regulators overlooked substantial threats to public safety before approving a new rule that would allow trains to deliver liquefied natural gas (LNG) in the Lower 48, environmental groups and a coalition of states argue in separate lawsuits filed this week.

LNG

An alliance of environmental advocates led by Earthjustice allege that, should a train derailment result in punctured tank cars and LNG escaping containment, the gas would expand rapidly and become highly flammable, posing explosion risks.

“It’s unbelievably reckless to discard the critical, long-standing safety measures we have in place to protect the public from this dangerous cargo,” said Jordan Luebkemann, an attorney for Earthjustice, which filed suit in the U.S. Court of Appeals for the District of...