According to the U.S. Geological Survey (USGS), in 2009, U.S. production of diatomite was estimated at 790,000 tons with an estimated processed value of $179 million, f.o.b. plant. Production took place at 7 diatomite-producing companies with 12 mining areas and 9 processing facilities in California, Nevada, Oregon, and Washington. World resources of crude diatomite are adequate for the foreseeable future. Transportation costs will continue to determine the maximum economic distance most forms of diatomite may be shipped and still remain competitive with alternative materials (USGS, Mineral Commodity Summaries 2010).