Delaware Supreme Court justices pushed back Wednesday on the argument that an increased likelihood of disease warrants class action recovery before the disease develops, asking questions on where and if courts should draw the line in holding defendants liable for preemptive medical monitoring costs.

The court has been asked by the U.S. Court of Appeals for the Third Circuit to provide guidance on where state law falls on claims from a group of New Castle County residents who say a Croda Inc. plant’s ongoing emissions of the gas ethylene oxide has quadrupled their risk of developing cancer.