Enbridge digs up leaking Illinois pipeline

CALGARY, Alberta Enbridge Inc on Saturday started digging up the pipeline that halted nearly a third of Canada's crude oil exports to the United States when it sprung a leak two days ago, but the company does not have an estimate on how long repairs will take.

Enbridge said removal of the damaged pipe is complicated by utility lines and sewer pipes near its line, forcing workers to dig by hand or use high-pressure water to expose the oil conduit. It can't yet say when that will be completed or when shipments might resume.

"Excavation has begun, but it's a busy corridor," said Gina Jordan, a spokeswoman for Enbridge. "There is still no estimate on when we can restart (the line)."

The leak was discovered around noon on Thursday at a stretch of pipeline in Romeoville, Illinois, about 30 miles southwest of Chicago. Enbridge quickly shut down its Line 6A, the largest of its three major lines that take Canadian crude to refineries in the U.S. Midwest and on to the Cushing, Oklahoma, oil storage hub.

The line can handle 670,000 barrels per day but was transporting about 459,000 bpd before the leak.

Canada shipped 1.75 million barrels of crude to the United States in the week to September 3, making it by far the largest foreign supplier. Saudi Arabia, the No. 2 supplier, shipped 1.16 million bpd to U.S. markets last week, according to data from the U.S. Energy Information Administration.

U.S. oil prices surged $2.20, or nearly 3 percent, on Friday as the leak on the 467-mile line from Superior, Wisconsin to Griffith, Indiana threatened to slash oil supplies to the Midwest.

The latest incident also comes less than two months after a smaller Enbridge line on the same Lakehead pipeline system that includes Line 6A was shut after spilling nearly 20,000 barrels in Michigan. Calgary-based Enbridge has still not been allowed to restart that line.

The U.S. Environmental Protection Agency is supervising Enbridge's clean-up at the spill site. It said on Saturday that the oil had been contained and the company was removing spilled oil in a retention pond near the site of the leak.

Some oil spilled into storm sewers, forcing the temporary closure of a waste-water treatment plant. However, that oil has also been isolated in the plant's lagoons and is beginning to be removed.

The EPA is still unable to estimate the size of the leak and said it was unsure whether oil continued to drain out of the damaged line.

"We haven't exposed the line yet so we don't know if oil is still leaking," said Sam Borries, the EPA's on-scene coordinator at the spill site. "But it's no longer bubbling up to the surface."

(Editing by Paul Simao)