BP Plc’s US chief faces accusations in Congress today that the oil supermajor has caused the worst oil spill in US history.

A day after BP shares fell 9% in London and New York, US lawmakers will ask Lamar McKay why BP made decisions that appeared to favour cost savings over safety before the Deepwater Horizon rig exploded on 20 April 2010.

Head of BP America McKay will be surrounded at the congressional hearings by executives from ExxonMobil, Chevron, ConocoPhillips and Royal Dutch Shell, who will be seeking to stave off repercussions for the industry, reports Reuters.

“This incident represents a dramatic departure from the industry norm in deepwater drilling,” ExxonMobil chairman and chief executive Rex Tillerson said in a prepared testimony.

The 20 April explosion in the Gulf of Mexico killed 11 workers and ruptured BP’s well. The spill has fouled 120 miles of US coastline, imperiled the local fishing and tourism industries and endangered wildlife.

President Obama will also wrap up a two-day trip to the Gulf of Mexico today before returning to Washington to give a televised speech aimed at seizing the political momentum of the clean-up operation.

BP shares steadied in early London trading on Tuesday, dropping by more than 2% before recovering to stand just 0.4% lower at 356.75 pence at 08.25 GMT, indicating a modest recovery in US trade, reports Reuters.

BP has hired investment banks Blackstone Group, Goldman Sachs Group and Credit Suisse Group as advisers, a source familiar with the issue said, but did not identify the purpose of the advice.