Hill prospered in the late 1970s, in part because of the explosion of local construction projects funded by the newly established United States Environmental Protection Agency (EPA). The EPA required the use of the Federal Acquisition Regulation and claims (as "Requests for Equitable Adjustments") became the new norm for local procurement. The firm had about 20 full-time employees by the end of 1979. In 1980 the firm opened its first branch office in Washington, D.C., and began to serve the U.S. government and government contractors from this location.By the 1980s another series of events in the construction industry fueled a further increase in construction claims and the growth of Hill - the construction of numerous nuclear power plants. The construction of these plants was highly regulated and resulted in overruns in cost and schedule for almost every plant built. Over 46 plants had been commissioned in the 1980s alone. At this time, the Nuclear Power Generating Industry was at the end of a rapid increase in constructing plants and began to terminate many projects. This decline had already begun due in large part to nuclear accidents at Three Mile Island and Chernobyl. This brought another explosion in construction claims for schedule and cost overruns as well as termination claims, including utilities, engineers, and nuclear reactor manufacturers as well as contractors and subcontractors. At this time, Hill brought in William J. Doyle to oversee the growth in nuclear related claims business. Doyle had built a small mechanical contracting company into one of the largest mechanical contractors in the nation, General Energy Resources, Inc., whose core business was subcontracting at nuclear power plant projects. Doyle then served as Senior VP of Northrop Corporation before he became an executive of Hill overseeing much of the nuclear claims work as well as other multi-million-dollar projects.