Marine Emergency Protocol and Hull Requirement Act of 2008 - Amends the Oil Pollution Act of 1990 to authorize the Coast Guard's appropriate sector commander, during a time of a terrorist or enemy attack, dangerously low visibility at sea or in port, an oil spill over 5,000 gallons, or any other period of enhanced danger as determined by the Secretary of Homeland Security, to assume direct authority over all vessels within the area and to issue any orders to ensure the health and safety of the individuals located in, and the environment of, the sector.
Declares that nothing in the amendments made by this Act limits or otherwise preempts any state from establishing a more stringent law or regulation.
Prohibits certain cargo vessels that carry a significant (as determined by the Secretary of the department in which the Coast Guard is operating) quantity of oil or petroleum-based fuel to power the vessel from operating in the navigable waters or the Exclusive Economic Zone (EEZ) of the United States without fuel tanks that have a double hull, or a double containment system as effective as a double hull, for the prevention of a fuel discharge. Phases in the prohibition over a specified period of years, based on vessel age and tonnage.