In an industry known for locking heads with environmentalists, BP has long managed to convince Americans that it is a responsible "green" corporation.
But that carefullycrafted "Beyond Petroleum" image led by its green-friendly chief executive Lord (John) Browne may be in jeopardy as BP deals with the latest blow to its US operations - the shutdown of its massive Prudhoe Bay, Alaska oil field after a spill from a corroded pipeline.
Closing the pipeline follows a rash of environmental and safety issues with which BP's US arm has dealt over the past two years, including a 2005 explosion at its Texas City, Texas, refinery that killed 15 workers.
Analysts say the latest shutdown may have limited impact on BP's finances and share price. But it could still be costly for the company in the United States.
"The wider implications for BP are more sentiment driven," Credit Suisse analyst Ed Westlake wrote in a research note.
"The company, consistently seen by the public as the 'greenest' energy company, will be hurt hard by these reports, particularly following hot on the heels of the blow-out at the Texas refinery, as well as explosions at Prudhoe Bay."
Credit Suisse said that future project approvals in the United States could be difficult given that BP attracted regulators' attention after the Texas City blast.
Citigroup called the pipeline shutdown the latest "slur on BP's US credentials" but said the effect on the bottomline would be minor. Even if production from the field - about nine per cent of BP's US output - was shut off for the rest of the year, it would reduce earnings by just two per cent this year, Citigroup estimated.
Investors have paid the price for BP's woes. Since March last year, BP's share price is up about 13 per cent, while Exxon Mobil's rose by 17 per cent, and ConocoPhillips' stock jumped more than 29 per cent in the same time period.
For more than a year, BP's US operations have been beset by problems.
"There's an emotional element to this," said John Parry of John S Herold.
