A federal appeals court on Tuesday allowed the state of Iowa to enforce a law that prevents local schools from imposing mask mandates, except for schools attended by students whose disabilities make them more vulnerable to severe illness if they get COVID-19.

The court found that a mask requirement is a reasonable accommodation for students with such disabilities and allowed a group of parents of disabled children to pursue a lawsuit that seeks to strike down the law.

Two members of a three-judge panel of the 8th U.S. Circuit Court of Appeals in Omaha found a previous federal judge’s decision to issue an injunction that blocked the state ban on mask mandates was too broad because it applied to all schools. The court sent the case back to the judge to narrow the injunction to apply to the 10 school districts the students attend.

“The issues presented by plaintiffs involve a discrete group of students: those whose disabilities require accommodations in the form of mask requirements in order to safely be present in their schools,” the court wrote. “To remedy plaintiffs’ injury, an injunction is necessary only as applied to their schools and districts.”

The judges sided with the parents and a disability rights group in concluding that their lawsuit can proceed in federal court denying motions by Iowa Gov. Kim Reynolds and Iowa Department of Education Director Ann Lebo to dismiss the case.

The panel found the parents likely will succeed because mask requirements constitute a reasonable modification and schools’ failure to provide this accommodation likely violates the federal Rehabilitation Act.