small pollution containment chamber known as the top hat

GULF of MEXICO - A small pollution containment chamber, known as the top hat, is lowered into the Gulf of Mexico by the motor vessel Viking Poseidon May 11, 2010. The chamber will be used in an attempt to contain an oil leak that was caused by the mobile offshore drilling unit Deepwater Horizon explosion. (USCG) 10Spill0511-G-8744K-007