This is a move sponsored by other US oil giants, including the likes of Exxon, designed to exploit BP's unpopularity in order to reduce or eliminate its competitive power in the industry. The sponsors are no doubt also behind current political moves to ban BP from future drilling off the US coast, with the ultimate aim of forcing it to sell its major assets or even to break up the company.
http://www.thisismoney.co.uk/markets/article.html?in_article_id=509145&in_page_id=3&position=moretopstories
The US politicians who are being sponsored here know full well that BP is a US company, and that neither the British nor the Scottish governments were approached or connected with BP over the release of Mr Megrahi, but they are playing to US opinion which is pretty ignorant of the facts in the case. No doubt they would like to get a share of Libyan oil, having been largely excluded by the Tony Blair deal, which put their noses badly out of joint.
I doubt whether any of this will ultimately get very far, since if BP goes down, then any hopes of it being able to pay for the clear-up in the Gulf of Mexico or compensate those who live there for the losses they have suffered would also go down the tubes - and so would the prospect of lots of fat legal fees to the many US lawyers who are already salivating in anticipation of the claims to come.
And if that happens, then President Obama, who has already declared that he, not BP, is ultimately reponsible, will have to pick up the tab. So I don't think he is finally going to sign it off.