This pamphlet provides information for the public on what to do if you encounter a tar ball. "Tar Balls are fragments or lumps of oil weathered to a semi-solid or solid consistency, feel sticky, and are difficult to remove from contaminated surfaces. They are formed through the combining of viscous hydrocarbons with debris that is present in the water column. They range in size from a pinhead to approximately 30 centimeters in diameter."
USCG Sector Mobile Digital Area Contingency Plan: http://ocean.floridamarine.org/acp/mobacp/