Cruise ships plying the waters of Glacier Bay National Park and Preserve in Alaska can approach the size of small towns, with thousands of passengers that require food services and wastewater management systems. On top of those waste generators, they use propulsion systems with fuels that could devastate the park's environment if leaks arise. Against that backdrop, the National Park Service has started an unannounced inspection system by which third-party inspectors will board ships to monitor their operations.