ZionNuclear Power Station was the third dual-reactor nuclear power plant in the Commonwealth Edison network and served Chicago and the northern quarter of Illinois. The plant was built in 1973, and the first unit started producing power in December 1973. The second unit came online in September 1974. This power generating station is located on of Lake Michigan shoreline, in the city of Zion, Lake County, Illinois. It is approximately 40 direct-line miles north of Chicago, Illinois and south of Milwaukee, Wisconsin. The Zion Nuclear Power Station was retired on February 13, 1998. The plant had not been in operation since February 21, 1997, after a control-room operator inserted the control rods too far during a shut down of Reactor 1 and then withdrew the control rods without following procedures or obtaining supervisory permission. Reactor 2 was already shut down for refueling at the time of the incident. ComEd concluded that the plant could not produce competitively priced power because it would have cost $435 million to order steam generators which would not pay for themselves before the plant's operating license expired in 2013. All nuclear fuel was removed permanently from the reactor vessel and placed in the plant's on-site spent fuel pool by March 9, 1998. Plans were to keep the facility in long-term safe storage until Unit 2's operating license expires on November 14, 2013. Decontamination and dismantlement were to begin after this date. The estimated date for closure was December 31, 2026. On August 23, 2010, it was announced that the Nuclear Regulatory Commission approved the transfer of Exelon's license to EnergySolutions of Salt Lake City. The company began the 10-year process of decommissioning the site and will eventually haul away pieces of the plant to its property in Utah. During the decommissioning process, the used nuclear fuel was transferred from the spent fuel pool into dry casks and placed into a newly constructed Independent Spent Fuel Storage Installation. The transfer procedures were completed in January 2015. The total cost of decommissioning is expected to reach approximately 1 billion dollars. After this is complete, Exelon will resume responsibility of the site, including the ISFSI. On February 14, 2013, a small fire broke out at the shuttered Zion nuclear plant, but authorities said it was put out with one extinguisher and there were no radiation leaks or risks to the public. Workers involved in the decommissioning of the plant were using torches to cut bolts when some grease began to smoke and produce small flames, said Mark Walker of EnergySolutions, the contractor handling the decommissioning. The power plant was the tallest structure in Lake County. A January 7, 2017Chicago Sun-Times article reported that the closing of the nuclear plant strongly and negatively affected the City of Zion economically.