The BP PLC oil spill in the Gulf of Mexico is the second-largest spill in world history -- and the worst caused by an accident -- according to flow-rate estimates released yesterday by federal scientists.

The new numbers peg the spill at nearly 20 times larger than the 1989 Exxon Valdez spill in Alaska, which was previously the country's worst spill.

Government scientists estimate some 2.6 million gallons of oil a day gushed from the ruptured well after the April 20 explosion. Models indicate the flow rate decreased to 2.25 million gallons of oil per day by the time the well was sealed in mid-July.

In total, the federal research team says, nearly 206 million gallons of crude escaped from the well over the 87 days the well was uncapped. Some of that oil was captured by BP's containment system, but 175 million gallons still sullied Gulf waters.

The 1979 Ixtoc 1 oil spill -- formerly the world's second-worst spill -- poured 143 million gallons of crude into Mexican waters after the well exploded. The 1989 Exxon Valdez spill -- formerly the worst U.S. spill -- leaked 10.8 million gallons after the oil tanker ran aground in Prince William Sound.

But while the new numbers peg the BP spill as the worst in U.S. waters and the worst caused by an accident, it still pales in comparison to the nearly 480 million gallons that spilled into the Persian Gulf during the Gulf War after Iraqi forces opened valves of oil wells and pipelines as they retreated from Kuwait in 1991.

The new federal numbers follow months of speculation about the size of the BP spill. In the early days of the spill, BP estimated the flow rate could be as low as 42,000 gallons a day. Later, it stood behind an estimate of 210,000 gallons a day until federal scientists in late May revised those numbers significantly upward.

The federal team raised its flow-rate estimate once more in June, estimating a range of 1.5 million to 2.5 million gallons per day. The more specific numbers released yesterday come as the federal teams of scientists have used containment cap and well integrity test data to narrow in on the estimate.

"Had BP owned up to the size and magnitude of this oil spill from the very beginning, the government and families in the Gulf would have been better prepared to respond to this tragedy," Rep. Ed Markey (D-Mass.) said in a statement. Markey has been a vocal critic of BP's early low flow-rate estimates and released the documents showing BP's initial estimate of 42,000 gallons a day.

"There is no joy in learning the true size of this horrific spill, but I hope that it will be a number that helps make families living and working in the Gulf coast whole once again," Markey added.

The new numbers could be used to help determine the size of the British oil giant's penalty. Federal law require companies involved in an oil spill to pay a per-barrel fine.

Markey said that fine could range from $1,100 per barrel to as much as $4,300 per barrel if gross negligence is found.

Based on the federal scientists' estimates and using Markey's figures, fines could range from $4.5 billion to $17.6 billion.

Leak derails static kill

BP's plans to begin the final steps of shutting down the well for good were waylaid after an injectivity test yesterday was postponed when a small hydraulic leak was discovered in the capping stack hydraulic control system.

The injectivity test -- a procedure that involves pumping oil from the surface down the wellbore to determine whether oil can be forced back into the reservoir -- is the final step before the British oil giant can conduct its so-called static kill, which will involve pumping some 2,000 barrels of heavy drilling fluids down the wellbore to force the oil back into the reservoir miles below the seafloor.

That static kill procedure will set the company up for its final cementing operations, which were expected to begin next week.

Retired Coast Guard Adm. Thad Allen said the injectivity test will resume later today, and the static kill could begin within hours after that test is complete.

BP sells Colombian assets

BP is selling its Colombian oil and gas business to Ecopetrol SA, Colombia's national oil company, and Talisman Energy Inc. of Canada for a total of $1.9 billion.

The sale comes as BP is attempting to raise some $30 billion in cash to pay for the cleanup effort in the Gulf of Mexico.

The company has previously agreed to sell assets in the United States, Canada and Egypt to Apache Corp. for $7 billion, and it has announced plans to sell assets in Pakistan and Vietnam.

Lawmaker wants idle rig workers to clean up abandoned rigs

Rep. Raúl Grijalva (D-Ariz.) is pressing Interior Secretary Ken Salazar to employ out-of-work oil rig workers to dismantle the hundreds of idle oil rigs and drilling structures in the Gulf of Mexico.

Recent analyses have shown there are more than 1,000 abandoned oil rigs and drilling structures sitting idle in the Gulf, Grijalva said, abandoned by their owners many years ago.

Federal regulations mandate removal of a rig that has been inactive for a year, but those regulations are not being fully enforced, Grijalva said.

"These structures ... now provide us with a unique chance to create jobs and open up future economic opportunities throughout the Gulf region," Grijalva wrote in a letter yesterday to Salazar. "By removing outdated structures, Gulf workers would help the structures' owners comply with existing regulations and ensure that cleared areas are open to potential future opportunities."

Click here to read Grijalva's letter to Salazar.