They were completed on February 7th. Once cleanup operations were complete, Federal, state and local officials discontinued response efforts. Protective booming strategies were rapidly employed at Mill Cove, the International Ferry Terminal and Veteran's Memorial Bridge. The boom was removed on February 7th when site assessment teams found no visible sheens or recoverable concentrations of dissolved styrofoam in the harbor. One of the presiding factors for that variance is the different behaviors the two oils have when released into the environment.
Gasoline spreads to a thin sheen and completely evaporates, leaving no residue.
Gasoline can partially dissolve into the water column, though evaporation is usually faster and limits the amount of dissolution. Under the spill conditions of rain and cold air and water, the amount of dissolved oil may persist longer than usual. The result could be localized fish kills, particularly in shallow water. Heavy Fuel Oil is a persistent black oil of which only a small amount is expected to evaporate. When spilled on water, heavy fuel oil spreads into thick slicks which can contain large amounts of oil.