BP CEO grilled by UK parliamentSTORY HIGHLIGHTS- NEW: Tony Hayward: "No evidence" chemical dispersants have entered the food chain
- American anger was "quite understandably" high after the spill, he says
- BP's outgoing chief executive says his company didn't skimp on blowout preventers
- Hayward was speaking to the British parliament's Energy and Climate Change Committee
London, England (CNN) -- Outgoing BP Chief Executive Tony Hayward denied Wednesday that cost-saving was the reason his company put only one blowout preventer on the well that exploded in the Gulf of Mexico in April, leading to one of the worst oil spills in U.S. history.
"There was no decision of that sort that was taken to save money," he said.
He said the blowout preventer that failed "should have functioned" and the industry needs to understand why it did not.
If it had worked as it was designed to, the consequences of the April explosion on the Deepwater Horizon "could have been very different," said top BP executive Bernard Looney.
Video: Tony Hayward out as CEO 
Video: Tony Hayward's downfall Hayward insisted that the company encourages staff to speak up, saying BP focused on "creating the right environment so that people feel they can raise their hand and speak up with respect to safety."
The BP executives were testifying before a British parliamentary committee investigating the implications of the Gulf oil disaster on deepwater drilling.
Hayward said there was "no evidence" that chemicals used to disperse the oil have entered the food chain.
In response to a question about his company's public-relations response to the spill, he said there are "many things" he would do differently "if I had the opportunity to do it again."
His mouth twisted in a wry smile as he responded, one of few moments of visible emotion during a hearing in which he appeared subdued. Wearing a dark blue suit and black-and-blue tie, he often spoke so quietly he was hard to hear.
He repeatedly referred to the Gulf spill as a "tragedy," and said American anger "was very high and quite understandably so," which made the situation "very difficult."
He refused to criticize the American government's reaction to the disaster, despite being encouraged to do so by British lawmaker Tim Yeo.
The Energy and Climate Change Committee is looking at the British government's refusal to impose a moratorium on deepwater drilling in Britain and whether existing safety and environmental standards need updating in light of the massive spill.
BP has extensive drilling operations in the North Sea off the coast of Scotland. Hayward said the environment in the North Sea is very different from that in the Gulf of Mexico.
And he said the financial pressure on his company after the Gulf spill has "no implications for our investment in the North Sea."
Hayward came under fire for his handling of the Gulf disaster. He will step down as chief executive on October 1.
As the head of the company, Hayward became a lightning rod for public and political anger after the drill rig operated by BP exploded in the Gulf of Mexico in April. The explosion and ensuing fire killed 11 workers and ruptured a well deep below the surface.
The spill, which Hayward himself called an environmental catastrophe, fouled large portions of the coastline in Louisiana, Mississippi and Florida. It has also crippled the Gulf Coast economy and led to a government-imposed moratorium on deepwater oil drilling.
The ban is currently the subject of a legal dispute.
Since he was thrust into the spotlight, Hayward has made a number of high-profile gaffes that critics say illustrated his lack of sensitivity for those hurt by the spill. In May, he botched an expression of sympathy by saying he wanted his life back, a slip for which he later apologized.
CNN's Melissa Gray and Jim Boulden contributed to this report.