As the federal government increasingly concerns itself with activites posing environmental dangers, federal initiatives increasingly preempt the traditional exercise of local police power to curb these activities.¹ When conflicts between state and federal regulatory efforts inevitably arise, the courts are often called upon to determine the extent to which federal regulation has supplanted this local authority to restrict activities that cause local harm.

On March 6, a divided Supreme Court made a cautious foray into the legal thicket surrounding the question of preemption to determine how far federal regulation of oil tankers had ousted the state of Washington's authority to regulate the size, design, and movement of the large tankers that use Puget Sound. In Ray v. Atlantic Richfield Company (Ray v. ARCO),² the court substantially affirmed³ the ruling of the three-judge lower court, holding that most of the restrictions on tanker design, size, and movement imposed by the Washington Tanker Law were preempted by the federal Ports and Waterways Safety Act (PWSA)⁴ and regulations issued pursuant to it.