In 1925, potash was discovered near Carlsbad, and for many years Carlsbad dominated the American potash market. Following the decline of the potash market in the 1960s, the residents and leaders of Carlsbad lobbied for the establishment of the Waste Isolation Pilot Plant (WIPP), a site where low-level nuclear waste would be stored thousands of feet underground in salt beds. Congress authorized the WIPP project in 1979, and construction began in 1980. The DOE Carlsbad Area Office opened in 1993, and the first waste shipment arrived in 1999.