William Eivind Hall (born 1942) is an American chemical engineer who became the CEO and Chairman of the American-based worldwide energy engineering company Parsons Energy & Chemicals based in Houston, Texas in 2000. The company used to be a division of Parsons Corporation. In 2004 Parsons Energy & Chemicals merged with an Australian engineering company and became WorleyParsons. From 2004 to now Hall has been an Executive at WorleyParsons. Before heading Parsons Energy & Chemicals he was President of Parsons Corporation. He has been a Director at the U.S.-Saudi Forum.