FAIRHOPE, Ala. — Coast Guard officials knew it was just a matter of time before crude oil from the Deepwater Horizon accident began washing ashore in Louisiana. Although traces of an oil sheen had been reported on land there earlier in the week, nothing was confirmed until heavier oil began showing up Thursday on Freemason Island, one of the land masses in the Chandeleur Island chain near St. Bernard Parish.

The floating drilling platform, which was located around 40 miles from the mouth of the Mississippi River, exploded April 20 and sank two days later. Despite the 24-hour efforts of crews on the scene, the BP-owned well continues to release roughly 210,000 gallons of light sweet crude into the Gulf of Mexico daily.

Secretary of the Interior Ken Salazar surveyed the ongoing response efforts on Wednesday, inspecting the four-story cofferdam that will be used in an attempt to capture oil spewing from the largest leak above the damaged well head. He also made an aerial survey of containment and cleanup efforts under way in Gulf waters, and visited the Bon Secour National Wildlife Refuge to assess on-the-ground efforts being made to protect sensitive areas here.

Speaking during a press conference, Salazar vowed to hold the petroleum giant’s feet to the fire.

“I looked at the dome, and am holding BP accountable,” he said. “I also looked at the drilling rig to make sure it was in place. I’m making sure we are protecting the fish and wildlife of the Gulf Coast.”

U.S. Coast Guard Rear Adm. Mary Landry noted the dome (cofferdam) is an important cog in the oil recovery process. She said, “We are all hoping this containment system will work, but understand this is the first of its kind deployed in 5,000 feet of water.”

The 65-ton, concrete and steel structure was lowered into position at the well site Thursday, and will be connected to the operations ship Enterprise and the riser system this weekend.

Designed to collect up to 85 percent of the oil now spilling into the Gulf, the cofferdam system is expected to begin transferring oil into tankers early next week.

If it proves successful, a second containment structure now under construction will be brought in to help control a smaller secondary leak. A third leak was stopped earlier when a valve was installed on the mangled riser pipe.

Landry said, “It’s very complex, and we will have challenges along the way. This is a serious spill, but there is a concerted effort to contain it. We have a lot at stake here, and everyone understands that. We are not going to stop; we are not going to back off until this thing is sealed.”

BP began drilling a relief well late last weekend, according to Doug Suttles, BP chief operating officer in charge of exploration. The 18,000-foot adjacent well is expected to take 90 days to complete, and is expected to relieve pressure off the main well and enable remote-controlled submarines to plug it with cement.

Chemical dispersants are also being used to break up the oil at both the surface and the source, and controlled burns are another tool helping reduce the amount of heavy surface oil, according to Suttles.

One additional option being considered is the installation of another blowout valve above a failed BOV that remote-operated submarines have so far been unable to shut off. Caution is the watchword, however. Suttles said, “We don’t want to do anything that will make it worse.”

A plan being implemented locally is the placement of oil containment booms across Mississippi Sound and the mouth of Mobile Bay in an attempt to prevent oil from entering from the vital estuary system. Both will utilize “swing-gates” with decontamination locks to enable commercial shipping to continue using both passages.

“We have to balance the impact of the spill with the possible economic impact,” Landry added.

Good weather is helping in the battle to keep oil away from the Alabama coast, Suttles said. Winds from the south and southwest are transitioning, with wind shifting to the northeast or east on Sunday. Officials expect the conditions to favor keeping oil away from southwest Alabama through the weekend.

“We’re trying to give a sense of the trajectory of the oil each day by using over-flights and satellite data. All states and local communities are preparing for landfall,” Landry said.

More than 700,000 feet of oil containment boom material has been deployed along the Gulf Coast so far, and 30,000 individuals have called to volunteer their assistance in the cleanup. Nearly 4,000 have been trained to handle hazardous material.

Suttles said, “We will continue to fight this on every front, and are committed to stopping the flow and mitigating the impact.”

The Interior Secretary on Thursday moved to stop the issuance of any additional offshore drilling permits through at least the end of the month. The move is expected to give federal investigators more time to determine what caused the explosion and subsequent valve failure. A report is due on President Barack Obama’s desk May 28.

Salazar said, “We have to (continue to) develop our own sources for oil and gas.” He pointed out that although the president recently decided to expand offshore drilling by authorizing rig placement in waters off Florida, California and other states, he remains committed to the development of new sources of alternative energies such as wind and solar power.

“We need to learn from this incident so there’s not another incident like this ever again,” Salazar said.