The department said on its Web site "sticky, dark-colored pieces of oil" had been discovered at South Pass in Plaquemines Parish on the southeast side of the Pass a Loutre Wildlife Management Area. Officials said the tar balls result when "weatherization changes the physical characteristics of floating oil."
A second oil containment box was being lowered into the Gulf of Mexico Wednesday to try to stop oil leaking since an April 20 explosion sank the Deepwater Horizon oil rig operated for BP by Transocean Ltd., BP officials said. Eleven workers died in the blast.
Doug Suttles, BP's chief operating officer for exploration and production, said the new device -- a 5-foot-tall, 4-foot-diameter structure called a "top hat" -- would keep most of the water out at the beginning of the capping process, allowing engineers to pump in methanol to prevent hydrate crystals from forming, CNN reported Wednesday.
Crystal formation was a main reason a larger containment vessel was unsuccessful in stopping the flow of oil from the wellhead about 5,000 feet below the surface.
The well spews about 210,000 gallons of crude into the gulf each day.
U.S. Interior Secretary Ken Salazar said the success of the second attempt to cap the well would be known within a few days, CNN reported.
"On this Thursday, we should know whether or not this alternative top hat cofferdam is going to work," Salazar told CNN. "And then the next key date is Saturday, because by Saturday they will have the diagnostics completed through X-rays and gamma rays and pressure ratings to be able to make decisions about what the next steps are ... ."
If the second attempt fails, BP said it may try to staunch the leak by shooting debris such as shredded tires, golf balls or other similar objects under high pressure into the well's blowout preventer. The blowout preventer did not fully close when the rig exploded and sank.
BP also is drilling a relief well to try to divert the flow to another pipe, Suttles said. It may take up to three months to reach the target area, BP said.
Meanwhile, the Biloxi Sun Herald reported wildlife officials were trying to determine whether the oil spill was to blame for the recent deaths of six dolphins in Mississippi, Louisiana and Alabama. The newspaper said a local expert's initial inspection of the carcasses showed no oil contamination and he considered a handful of deaths over such a large region to be within normal parameters.