The San Onofre Nuclear Generating Station (SONGS) is an inoperative nuclear power plant located on the Pacific coast of California, in the northwestern corner of San Diego County, south of San Clemente, and situated in Nuclear Regulatory Commission Region IV. The plant is currently in the initial stages of preparation to be decommissioned after being closed in 2013 following the failure of recently replaced steam generators.The nuclear facility is owned by Southern California Edison. Edison International, parent of SCE, holds 78.2% ownership in the plant; San Diego Gas & Electric Company, 20%; and the City of Riverside Utilities Department, 1.8%. When fully functional, the plant had employed over 2,200 people. The station, between the ocean and Interstate 5, is a prominent landmark because of its twin spherical containment buildings, designed to contain any unexpected releases of radiation.The plant's first unit, Unit 1, operated from 1968 to 1992. Unit 2 was started in 1983 and Unit 3 started in 1984. Upgrades designed to last 20 years were made to the reactor units in 2009 and 2010; however, both reactors had to be shut down in January 2012 due to premature wear found on over 3,000 tubes in replacement steam generators that had been installed in 2010 and 2011. The Nuclear Regulatory Commission is currently investigating the events that led to the closure. In May 2013 Senator Barbara Boxer, chairman of the Senate Environment and Public Works Committee, said the modifications had proved to be "unsafe and posed a danger to the eight million people living within 50 miles of the plant,” and she called for a criminal investigation.Southern California Edison announced on June 7, 2013 that it would "permanently retire" Unit 2 and Unit 3, citing "continuing uncertainty about when or if SONGS might return to service" and noting that ongoing regulatory and "administrative processes and appeals" would likely cause any tentative restart plans to be delayed for "more than a year." The company stated that "Full retirement of the units prior to decommissioning will take some years in accordance with customary practices. Actual decommissioning will take many years until completion."