Construction on Byron Nuclear Generating Station began in 1975, at a 1,782-acre (7.2 km) site, 17 miles (27 km) southwest of Rockford, Illinois, south of the city of Byron in Ogle County. The firm of Sargent & Lundy acted as consulting engineer during construction and Babcock & Wilcox oversaw the completion of the reactor vessels. Before construction was completed on the reactor vessels and facilities, at least three groups joined in a 1981 lawsuit to halt Byron Nuclear Generating Station's completion. The League of Women Voters, DeKalb Area Alliance for Responsible Energy, and others were involved in the lawsuit over the safety of and need for the plant. In 1984 the Atomic Safety and Licensing Board, a division of the U.S. Nuclear Regulatory Commission (NRC), stopped the planned nuclear station at Byron by refusing its owners, then Commonwealth Edison, permission to begin operation. The decision stemmed from concerns about the quality control of independent contractors hired during construction. Ultimately, the board overturned its decision in October 1984 and permission was granted to operate after a re-inspection of over 200,000 items and components within the plant.