## Facts

- After a 2003 oil spill in Buzzards Bay, Massachusetts enacted the Massachusetts Oil Spill Prevention Act (MOSPA) to reduce spill risks in state waters.
- MOSPA and related regulations imposed, among other measures, tug-escort requirements for certain tank vessels in Buzzards Bay, specified manning and watchkeeping rules, and operational prescriptions affecting vessel movement and pilotage.
- Federal law regulated the same general subject through the Ports and Waterways Safety Act (PWSA), the Oil Pollution Act of 1990 (OPA), and Coast Guard regulations, including a Coast Guard Vessel Traffic Service (VTS) for Buzzards Bay addressing routing and certain safety requirements.
- The United States and shipping-industry groups sued Massachusetts in federal district court seeking declaratory and injunctive relief, alleging MOSPA provisions were preempted by federal law.
- The district court granted summary judgment largely for the plaintiffs, declared most challenged provisions preempted, and enjoined Massachusetts from enforcing them.
- Massachusetts and an intervening environmental group appealed.

## Issues

1. Whether MOSPA’s tug-escort, manning/watchkeeping, and related operational requirements were preempted under PWSA and Coast Guard regulations (by field or conflict preemption).
2. Whether OPA savings provisions preserved state authority to impose additional spill-prevention measures despite PWSA-based preemption rules.
3. Whether the district court’s declaration and injunction were overbroad and insufficiently tailored to provision-specific preemption analysis.

## Decision

- The First Circuit affirmed in part, vacated in part, and remanded.
- It affirmed preemption of MOSPA’s manning and watchkeeping provisions as inconsistent with the federal scheme governing crewing and vessel operations.
- It vacated the categorical preemption ruling and corresponding injunction as to certain tug-escort and related operational provisions, directing further evaluation in light of the Coast Guard’s evolving Buzzards Bay regulatory actions and factual record.
- It criticized the breadth of the injunction and required narrower relief tied to specific provisions shown to be preempted.

## Legal Principles

- Under PWSA and controlling Supreme Court precedent, when Congress and the Coast Guard regulate a maritime-safety subject with comprehensive national standards, state rules intruding on that subject are generally preempted to avoid non-uniform requirements on interstate and international shipping.
- OPA’s preservation of certain state authority (including in areas such as liability and financial responsibility) does not eliminate PWSA-based preemption for navigation and vessel-safety standards.
- Manning and watchkeeping requirements are closely tied to uniform federal regulation; states may not impose additional crewing and watch standards on vessels subject to Coast Guard rules.
- State regulation may sometimes address distinct local maritime hazards, but only if it does not conflict with federal requirements and is not displaced by a federally occupied field.
- Preemption and injunctive relief must be provision-specific; courts should not invalidate or enjoin broader statutory and regulatory provisions beyond those shown to be preempted.

## Conclusion

The First Circuit upheld federal preemption of Massachusetts’s MOSPA manning and watchkeeping rules, but vacated the broader ruling that swept in tug-escort and related provisions, and remanded for a more targeted, updated preemption analysis and a narrower injunction tied to demonstrated conflicts with federal law.


United States v. Massachusetts, 493 F.3d 1 (1st Cir. 2007)