New BP PLC Chief Executive Tony Hayward is making sweeping moves to clean up the oil giant's operational and regulatory troubles. Among them: an expected agreement to plead guilty to U.S. criminal environmental charges and pay a $50 million fine related to a deadly Texas refinery explosion two years ago, according to people familiar with the matter.

The London-based company also is expected to pay $303 million to settle civil charges and avoid criminal prosecution in the U.S. for allegedly manipulating and cornering the propane market in 2004.