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(Adds size of spill, detail on cleanup, changes dateline)
By Karl Plume and Edward McAllister
Whiting, Indiana, March 25 (Reuters) - Oil leaked from BPPlc's Whiting refinery in Indiana into LakeMichigan after a malfunction at a recently upgraded processingunit on Monday afternoon, the company confirmed on Tuesday.
Between 10 and 12 barrels, or around 500 gallons, of crudeoil spilled into the lake, according to a local CBS reportciting a source. That would make this a relatively smalldischarge; last week, a pipeline owned by Sunoco LogisticsPartners spilled 240 barrels into an Ohio nature preserve.
The leak had stopped on Tuesday and no injuries werereported, London-based BP said in a statement. It declined tocomment on the volume of oil spilled.
As crews worked on the cleanup on this industrial stretch ofshoreline, the effect on Lake Michigan was not immediatelyclear. Two dozen workers were shoveling up sand on the shorethat looked lightly tarred by oil. A vacuum truck was sucking upoily water.
Oil spills are not uncommon in the United States, wheredrilling is at an all-time high and energy production is on therise. Still, Monday's spill will probably spur moreenvironmental opposition to the Whiting refinery, which has beenunder local scrutiny for releasing pollutants into LakeMichigan.
The spill may also be another blow to BP, whose reputationwas tarnished by the Macondo well blowout in the Gulf of Mexicoin April 2010. That was the worst offshore spill in U.S.history, spewing millions of barrels of oil into the ocean.
Only this month was BP allowed to bid again on new federaldrilling leases after a two-year government ban was lifted.
"It's troubling to hear that this spill occurred," saidLyman Welch, Water Quality Program Director at the Alliance forthe Great Lakes group. "It's a reminder that even whenprecautions are taken, spills occur into the Great Lakes and weneed to be vigilant to protect out drinking water supplies."
BP laid down containment boom on the water and said the oilwas confined to a cove between the refinery's wastewatertreatment plant and a steel mill.
Winds pushed the oil toward the shore and cold temperatureswere causing it to harden into a waxy consistency, making iteasier to collect, BP spokesman Scott Dean said.
"I've had no reports of any wildlife impacted," said Dean.
The U.S. Environmental Protection Agency, the Coast Guardand state regulators were at the scene.
OLD DISPUTES
The largest crude distillation unit at the405,000-barrel-per-day refinery was operating normally again onTuesday after a malfunction led to the leak, Dean said.
The 260,000-bpd crude distillation unit, called Pipestill12, was the centerpiece of a $4 billion refit of the Whitingrefinery completed late last year to run large amounts of oilfrom Canada's tar sands fields in Alberta.
A crude distillation unit does the initial refining of crudeoil coming into a refinery and provides feedstock for all otherunits at the plant.
The refinery has been increasing the amount of Canadiancrude oil running through Pipestill 12 during the first quarterof this year.
Environmental groups opposed the BP upgrade, saying use ofthe Canadian crude would increase pollution from the refineryinto Lake Michigan.
The Whiting refinery is the primary focus of BP's U.S.refining strategy to use only plants in the northern UnitedStates that have in easy access to Canadian crude oil. BP soldplants in Texas and California last year as part of thestrategy.
BP's American depositary shares were up 0.8 percentat $47.09 in afternoon New York Stock Exchange trading. Thecompany's stock rose 1.2 percent in London. (Reporting by Edward McAllister, Selam Gerekidan and JoshuaSchneyer in New York, Arpan Varghese in Bangalore, Erwin Sebaand Kristen Hays in Houston and David Sheppard in London;Editing by Lisa Von Ahn, Jeff Benkoe and Marguerita Choy)
