(CNN) - The Gulf oil disaster "never should have happened," and BP Chief Executive Tony Hayward says he is "deeply sorry" that it did.
Hayward is scheduled to appear Thursday at a House subcommittee hearing on the oil rig explosion and fire that killed 11 workers and set off the worst environmental disaster in U.S. history. In written testimony obtained by CNN, Hayward repeatedly says he is fully aware of the harm caused to the Gulf Coast region and commits BP to "do what we can to make certain that an incident like this does not happen again."
"Let there be no mistake - I understand how serious this situation is," Hayward's testimony says "This is a tragedy: people lost their lives; others were injured; and the Gulf Coast environment and communities are suffering. This is unacceptable, I understand that, and let me be very clear: I fully grasp the terrible reality of the situation."
Hayward says he was personally devastated by the deaths of the 11 workers and called attending their memorial service "a shattering moment."
"I want to offer my sincere condolences to their friends and families - I can only imagine their sorrow," Hayward says in the written testimony. "My sadness has only grown as the disaster continues."
Saying he wants to speak directly to the people of the Gulf region, Hayward adds: "I know that this incident has profoundly impacted lives and caused turmoil, and I deeply regret that." He notes that many of BP's 23,000 U.S. employees live and work in the Gulf Coast region, and that BP has always tried to be "a good neighbor."