The Wisconsin Supreme Court on Tuesday heard oral arguments in a case that could upend the Department of Natural Resources’ (DNR) authority to enforce the state’s decades old spills law, which allows the agency to hold companies and property owners responsible for toxic contamination.

The justices seemed unconvinced by the argument that the law governing chemical spills is overly vague, and appeared in favor of offering state officials flexibility on enforcement.

The Wisconsin Supreme Court will hear oral arguments in a pair of cases that present two questions at the core of an ongoing struggle between some of the most powerful forces in the state.