"If the moratorium is continued through June, lost revenue from shallow water drilling is estimated at 135 million," a group of senators said in a letter to Obama urging a lifting of the ban.

How much more the oil industry will have to pay for royalties or spill prevention, plus restricted access to new drilling sites, remains to be seen.

Tourism, the second largest industry in the Gulf following the oil and gas industry, accounts for about 46 percent of the Gulf economy, or over 100 billion dollars a year, according to the A&M report. And the impact of the spill on tourism is evident.

In Florida, state tourism officials say they are getting cancellations as far as three months out. It's even worse in Mississippi, where officials say cancellation rates are running at nearly 50 percent due to the spill.

Fishing, which generates 1.8 billion dollars a year, is perhaps the most directly affected by the BP spill. The government has already closed more than 30 percent of the federal waters for fishing activities, and many fishermen are out of work.

The fishing ban is especially disappointing because this year's harvest was expected to be the best since 2000, said Clint Guildry, president of the Louisiana Shrimpers Association.

All those industries' costs will eventually be billed to BP, which was leasing the Deepwater Horizon rig that exploded in late April off the Lousiana coast and triggered the worst oil spill in the U.S. history.

BP has spent 1.4 billion dollars, which includes the cost of the spill response, containment, relief well drilling, grants to the Gulf states, claims paid and federal costs. The figure excludes the 360 million in funds for the Louisiana barrier islands construction project.

BP expects the total bill for the clean-up to be 4 billion to 8 billion dollars, though many stock analysts predict the cost will be much higher. The British oil giant has lost tens of billions of dollars from its market value since the rig explosion.

As the oil leak has only been partly contained and oil continued to spew into sea, nearby states, businesses, environmental regulators and injured workers and cleanup crews are eyeing damages that could total billions more.

"This will be the mother of all liability claims," said Fred Kuffler, a Philadelphia maritime lawyer with experience in oil-spill lawsuits.