Port Eads, La. — In 2004, Hurricane Ivan plowed across the Gulf of Mexico and triggered an oil spill that is still leaking. It's the longest continuous oil spill in American history.

Captain Rick Jiannuzzi took CBS News to where the Taylor oil rig once stood.

"Wherever it looks smooth, that's all the sheen," he said.

From the air, that sheen is visible for miles and you can even see it from space. Fifteen miles out, you can also smell it.

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In 2004, Hurricane Ivan destroyed the MC20 oil platform operated by Taylor Energy. The company has spent over $400 million working alongside the U.S. Coast Guard to contain and clean up the spill which Taylor estimates has been leaking at a rate of about ten gallons a day for years.

But Florida State oceanographer and oil spill expert Ian MacDonald, who has studied the site for the government using underwater technology, thinks the leak is closer to 96 barrels a day. MacDonald convinced the Coast Guard that more oil is leaking than previously thought.

"We're talking about coming up on half a million barrels of oil," he said. "What's happening now is the Coast Guard and the government is saying wait a minute, we're going to take charge because we think that you're underestimating the amount of oil."

In a statement to CBS News, the company said, "Taylor Energy is raising the alarm about the junk science the Coast Guard is now using to justify activities that could destabilize the site."

The Coast Guard is now working with a private contractor to cap the well and will demand Taylor Energy pay the bill. But the fight over the spill has moved from the Gulf to a courtroom because Taylor has pursued legal action to block the containment.

Until the leak is stopped and the courtroom battle ends, we won't know how the spill will affect the marshlands or the fish and wildlife.