Costner's high-speed centrifuge machine has a Los Angeles-perfect name: "Ocean Therapy."
Placed on a barge, it sucks in large quantities of polluted water, separates out the oil and spits back 97% clean water.
"It's like a big vacuum cleaner," said Costner's business partner, Louisiana trial lawyer John Houghtaling.
"The machines are basically sophisticated centrifuge devices that can handle a huge volume of water," he said.
The "Field of Dreams" star first got a team together to create the device in the wake of the 1989 Exxon Valdez spill in Alaska.
His scientist brother, Dan Costner, helped develop the device, and together, the brothers formed Costner Industries Nevada Corp. to pursue various energy projects, including a non-chemical battery that could last 15 years.
The 55-year-old actor eventually sank $26 million into the Ocean Therapy oil separator project. He obtained a license for the device from the Department of Energy in 1993 and has been trying for years to promote it.
British Petroleum - desperate for ideas - gave the okay to test six of Costner's gizmos this week, said BP Chief Operating Officer Doug Suttles.