Whether federal solid-waste legislation preempted New Jersey's ban on importing most out-of-state waste.
Holding
No. Congress did not preempt New Jersey's regulation of waste disposal and transportation.
Reasoning
The Court found no clear and manifest congressional purpose to occupy the entire field of interstate waste management or transportation. Neither the Solid Waste Disposal Act nor its later amendments expressly displaced state authority over the subject.
Congress had instead indicated that the collection and disposal of solid waste should remain primarily a function of state, regional, and local agencies. The New Jersey statute also did not directly conflict with any particular federal provision or frustrate the basic federal program, so it could coexist with federal law.