From the company's uncommon well design to its fatal decision not to circulate drilling mud, which could have cleared out pockets of gas, and the lack of critical testing, which could have pinpointed problems with its cementing, the company had many points at which it could have prevented an explosion, investigators with the House Energy and Commerce Committee have found.

Instead, the company violated industry guidelines and proceeded "despite warnings from BP's own personnel and its contractors," said the chairman of the committee, Rep. Henry Waxman, D-Calif., and the chairman of the investigative subcommittee that handled the probe, Rep. Bart Stupak, D-Mich.

Those decisions led to 11 deaths and the worst oil spill in U.S. history and will continue to have an effect on the environment and the future of offshore drilling in the Gulf of Mexico, the two wrote in a letter to BP Chief Executive Officer Tony Hayward that was released Monday.

"Time after time, it appears that BP made decisions that increased the risk of a blowout to save the company time or expense," they wrote. "If this is what happened, BP's carelessness and complacency have inflicted a heavy toll on the Gulf, its inhabitants and the workers on the rig."

The committee will ask Hayward to address its findings Thursday, when it examines some of the root causes of the accident. The day before, Hayward is set to meet with President Barack Obama.

Tuesday, top executives with Exxon Mobil, Chevron, ConocoPhillips and Shell as well as BP will face the committee's Energy and Environment Subcommittee. The grilling is expected to put the companies in the position of distinguishing their safety practices from BP's. It will be the first time the executives have appeared together since Congress probed high gas prices in 2008.