The explosion of the Deepwater Horizon rig and the estimated 42,000 gallons of oil gushing daily from an underwater well into Gulf of Mexico waters are providing fresh fodder for congressional foes of offshore drilling. They have seized on the disaster as evidence that offshore drilling threatens the environment, human life, fishing industries and coastal states' tourism dollars.

The success of the massive recovery and containment mission now under way will influence the near-term future of offshore drilling, said Ken Medlock, a fellow in energy economics at Rice University's Baker Institute for Public Policy. Possible outcomes include a decision by the Obama administration to shelve some offshore lease proposals or stalled congressional plans for expanded drilling.

ï¿½It really does depend on how bad this gets,ï¿½ Medlock said. ï¿½If this drags out for monthsï¿½ and oil starts affecting ï¿½local businesses that rely on marine life, it's not just an issue of environmental costs. It also becomes a very real issue of economic costs.ï¿½

ï¿½Up in arms'

Sen. Bill Nelson, D-Fla., a longtime drilling opponent, said conservative business leaders ï¿½all along the Gulf Coast ï¿½ are up in arms and alarmed now and are scared to death that oil is moving toward themï¿½ ï¿½ and that fear is growing among state politicians and on Capitol Hill.

ï¿½If this thing keeps leaking a thousand barrels of oil a day (for months) it will drive a stake in the heart of drilling close to shore,ï¿½ Nelson said. ï¿½The fear and the panic that has been engendered as a result of this catastropheï¿½ could erode congressional support for new offshore drilling.

The issue is likely to spill over into a possible Senate debate later this year on combating climate change and revamping U.S. energy policy.

Senators negotiating a broad climate change and energy bill have included expanded offshore drilling in the plan in an effort to lure enough support from Republicans and oil-patch Democrats to pass the legislation.

For instance, the measure is expected to give coastal states the power to allow drilling in waters as far as 35 miles out from their shorelines ï¿½ compared to the typical three-mile boundary. The legislation also could give more coastal states a chance to collect lucrative royalty revenue from nearby offshore drilling.

If even a few senators withdraw their support from the bill because of the drilling issue, the whole compromise could unravel. ï¿½This might actually sway, at the margin, four or five Senate members,ï¿½ Medlock said, ï¿½and that may be all you need.ï¿½

Congress will play a key role in deciding whether to open up parts of the eastern Gulf of Mexico up for drilling leases. Right now, the area is walled off under a statutory moratorium that would have to be lifted before the Obama administration could follow through on plans to allow new drilling there.

ï¿½That may be an area where this tragedy may come into play,ï¿½ said Michael Olsen, a lobbyist with Bracewell & Giuliani who spent five years as a deputy assistant secretary in the Interior Department. ï¿½If the opponents of expanded drilling can drum up enough opposition among their colleagues, then, potentially, Congress won't have to lift that moratorium.ï¿½

ï¿½The other side'

Rep. Gene Green, D-Houston, a drilling advocate, said he hasn't seen signs yet that the images of the fire-engulfed rig or oil-covered waters have caused fellow congressional supporters of offshore drilling to change their minds on the issue. But he worries it could ï¿½give ammunition to the other side.ï¿½

ï¿½This is the first major spill since 1979 in the Gulf of Mexico (and) we have a really good history,ï¿½ Green said. But ï¿½when you watch it on TV, every news cycle, it keeps on people's minds.ï¿½

Although President Barack Obama last month proposed drilling along the Atlantic seaboard and in the eastern Gulf of Mexico, the Interior Department is at the very beginning stages of implementing the plan by accepting public comments on the scope of required environmental reviews.

Interior Department spokesman Kendra Barkoff said that before production could advance in new areas of the Gulf or Atlantic and Arctic oceans, the regions ï¿½will have to undergo thorough environmental analysis, public input and comment, scientific study and review and a careful examination of the potential risks and spill response capabilities in that area.ï¿½

The White House has not signaled it will change course on the drilling plan.

Sen. Robert Menendez, D-N.J., a leading opponent of expanded ocean drilling, said he hopes the disaster will convince wavering colleagues about the potential risks of offshore energy production.

jdlouhy@hearstdc.com