The top federal official in charge of the Gulf of Mexico oil spill response effort said the procedure aimed at killing the ruptured Macondo well should begin the week after Labor Day.

Retired Coast Guard Adm. Thad Allen's comments come a day after he refused to publicly set a timeline for the long-awaited "bottom kill" of the Macondo well.

But speaking today on CNN, Allen said federal and BP PLC officials have agreed to a sequence of procedures and tests to ensure the blowout preventer and well can withstand any pressure that might be generated during the bottom kill procedure.

"If all that lines up, we should be looking somewhere at the week after Labor Day," Allen said. Labor Day is Monday, Sept. 6.

Bottom kill involves pumping cement into the wellbore near the top of the reservoir miles below the seafloor to permanently seal the well.

The well has not leaked any oil into the Gulf for more than a month since BP sealed the top of the well with a tight-fitting cap, but weather and technical issues have hindered efforts to permanently shut it down.

Two weeks ago, BP injected mud and cement into the top of the wellbore to stanch the flow of crude and plug it. They had planned to immediately follow that procedure with the bottom kill, but Allen said BP and government engineers and scientists were concerned that the cement at the top of the wellbore may have trapped some 42,000 gallons of oil in the space between the well pipe and surrounding rock layers.

The scientists and engineers want to ensure that pumping mud and cement through the relief well into that space will not force the oil up, where it could leak into the sea or damage the failed blowout preventer that will be a crucial part of investigations into the April 20 blowout.

Separately, Allen today directed BP to replace the blowout preventer on the failed well.

White House panel considers more self-regulation for oil industry

A presidential commission tasked with investigating the causes and effects of BP's oil spill may push for the oil industry to create a self-regulating agency to fill a gap in the sector's oversight, one of the panel's leaders said yesterday.

The commission's co-chairman, Bill Reilly, told Reuters that an agency modeled on the nuclear industry's Institute of Nuclear Power Operations would allow oil companies working offshore to hold their counterparts more accountable.

"An INPO-like facility very strongly backed by a regulatory authority, by the government, could really fill that gap," the former U.S. EPA administrator said.

Such an agency would not substitute for a strong federal regulator, Reilly said, but instead would act as a supplement.

The panel will examine the details of how such an agency might work within the oil and gas industry during its second public hearing next week, Reilly said.

Falling public concern about spill

Public concern over the Gulf of Mexico oil spill has dropped sharply in the last two months after BP capped the well, according to a new poll.

Sixty percent of respondents in the new Associated Press-GfK Group poll said they view the spill as extremely or very important, down from 87 percent who held that position in a mid-June poll. In the updated survey, 25 percent view the spill as moderately important.

More broadly, the survey of 1,000 adults last week shows that 50 percent approve of the way Obama is handling the environment, and 47 percent approve of his handling of energy policy. A mid-July poll pegged Obama's rating on energy at 50 percent.

Sixty percent of respondents said they viewed the environment as extremely or very important, a level generally in line with pollster's results over the last year. Sixty-four percent called energy extremely or very important, down from 74 percent in mid-June and 73 percent in May.

The poll has a margin of error of plus or minus 4.5 percentage points.