Workers last week removed the final piece of the metal sheet pile cofferdam from the barge Davy Crockett work site on the Columbia River near Camas, Wash. This effectively signals the end of a 10-month effort to prevent a catastrophic release of oil and other hazardous materials from the former Liberty ship. Constructed in April 2011, the 850-linear foot cofferdam and impermeable liner allowed crews to systematically dismantle the derelict barge in the river and keep any pollution generated by the project to be contained and properly handled within.