U.S. tort costs increased by 5.1 percent in 2010, driven by the April 2010 Deepwater Horizon drilling rig explosion and resulting oil spill in the Gulf of Mexico, Towers Watson reports. In its 2011 Update on U.S. Tort Cost Trends, Towers Watson notes that absent the cost from this event, tort costs would have shown an overall decrease of 2.4 percent in 2010.