A federal appeals court will hear oral arguments March 16 in a case challenging EPA Administrator Scott Pruitt’s authority to delay an Obama-era chemical safety regulation aimed at protecting emergency responders.

The Obama administration issued the rule last year in the closing days of the administartion, setting new emergency response and information sharing requirements for high-risk chemical facilities. The changes—originally meant to take effect this March—would substantially update the EPA’s risk management program, a set of regulations authorized under the...