Forty-nine vessels - oil skimmers, tugboats barges and special recovery boats that separate oil from water - were meanwhile working to round up oil, BP said.

BBC: Growing concerns over Gulf of Mexico oil leak

But he said the oil was contained and skimmers would work nonstop.

NPR: Oil Leak: Miss. River At Vicksburg Remains Closed

There are smaller slicks of oil identified by planes, radioed to boats, skimmers sent to intercept those pockets of oil.

WHITEHOUSE: Press Briefing

An operation was being mounted to contain and clean-up the spill, including skimmers, booms to contain the oil and aeroplanes to drop dispersants on it.

BBC: Tackling oil rig disaster 'number one priority' - Obama

The state of Louisiana said Tuesday that of 343 operational skimmers, only 40 were sent out Monday in search of oil -- and they came back to shore with 100 cubic yards of debris, but not even one gallon of oil.

CNN: Allen: 'Our first goal is to do no harm' in Gulf

Mechanical systems like skimmers, centrifuges, and reverse osmosis machines can go a long way towards separating oil from water.

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