Sulfur, one of the major natural resources of Texas, occurs in important commercial quantities in the calcite caprock of some of the salt domes on the Coastal Plain, in the Permian Castile gypsum in numerous localities, and in secondary gypsite material in the Toyah Basin of Culberson and Reeves counties. The earliest sulfur deposits in Texas to attract attention were discovered in 1854 in an extension of the Toyah Basin in Permian gypsum deposits near the surface. Several geologists made reports on this area. Until the opening of the sulfur deposits on the coast, it was believed that the Toyah Basin deposits offered distinct commercial possibilities, but there had been only small-scale production in that area. Sulfur in dome deposits was discovered in Calcasieu Parish, Louisiana, in 1865, but because domes are overlain by quicksand, extraction by ordinary methods was not possible. In 1891, a liquid extraction process invented by Herman Frasch was patented. In the Frasch process wells are drilled into deposits, the sulfur is melted with superheated water, and the molten sulfur is forced to the surface. The process did not prove practical because of the high cost of heating fuel. In 1903, after the opening of the Spindletop oilfield reduced the price of oil, the Union Sulphur Company began significant commercial sulfur production in Louisiana. By 1906 this effort had not only substantially reduced American imports of sulfur, but also enabled American sulfur to enter European markets. In that year a large dome was located at Bryan Mound in Brazoria County, Texas. After the Frasch patents expired in 1912, the Texas Freeport Sulphur Company was organized to exploit the Bryan Mound deposits, from which production had been small. Miners discovered the Big Hill Dome in Matagorda County in 1908, and in 1909 the Texas Gulf Sulphur Company was organized to develop it. Little was done, however, except exploratory drilling and leasing until 1918, when the firm began construction of a plant. Production from Big Hill began in March 1919 and reached a half million tons the first year. The Freeport Company opened a second dome in 1922 (leased in 1920 from the Texas Company, now Texaco) at Hoskins Mound, Brazoria County, and in 1925 began production from the Allen Dome (leased from Roxana Petroleum Company). Boling Dome, in Wharton County, the largest known deposit, was opened by the Texas Gulf Sulphur Company in 1928, and in 1929 the company began production from a deposit at Long Point in Fort Bend County.
The discovery of sulfur deposits in salt domes resulted largely from exploration for oil. From the Gulf Oil Corporation, Humble Oil and Refining Company (now Exxon), and the Shell Oil Company, the Freeport Company obtained a lease in 1932 on the Grand Ecaille Dome in Louisiana and extended its operations to that state in 1933. The Union Sulphur Company had succumbed to Texas competition in 1924, but in 1932 a third organization, the Jefferson Lake Oil Company, began to exploit the Jefferson Island Dome in Louisiana. Although much smaller than the other two sulfur-producing companies, this firm soon opened production in Brazoria and Fort Bend counties, Texas. Sulfur was subsequently produced at the Texas Gulf Newgulf plant in Wharton County and at a fourth small company, the Duval Sulphur Company, in Fort Bend County.
Over the years Texas has produced about 80 percent of the sulfur supply of the United States and, with the smaller Louisiana production, has furnished a major part of the world's supply. By value of annual production, sulfur is the state's fourth ranking mineral and accounts annually for about 3 percent of its total mineral production value. Texas at times has produced more than 90 percent of the nation's sulfur. In 1954 Texas sulfur production by the Frasch process amounted to 3,450,000 long tons valued at $75,100,000. In addition, sulfur was also being recovered from sour gas. In the 1960s, exclusive of the oil-gas group, sulfur was the state's most valuable mineral. Texas remained one of the world's leading sulfur-producing areas. Frasch production was concentrated in Fort Bend, Jefferson, Liberty, Matagorda, and Wharton counties, and in underground Permian strata in Pecos County. Expanded storage shipment and the use of molten sulfur made possible significant changes: large tankers carried molten sulfur to the Netherlands, while barges transported Texas sulfur to inland markets. In 1965 Texas Frasch sulfur amounted to 3,674,000 long tons valued at $83,282,000. In 1966 two new sulfuric acid plants were completed at Houston and Port Arthur. Major oil firms explored tidelands leases offshore for sulfur production through sour-gas purification, and other exploration and leasing took place in Pecos, Culberson, and Duval counties. By 1970 plants were extracting sulfur from sour gas in Andrews, Atascosa, Cass, Cochran, Crane, Ector, Franklin, Gaines, Harris, Hockley, Hopkins, Jefferson, Karnes, McMullen, Moore, Rains, Reagan, Van Zandt and Wood counties. Five producers obtained sulfur in molten form through wells drilled into the caprocks of salt domes in Fort Bend, Galveston, Jefferson, Liberty, Matagorda, and Wharton Counties and into subsurface Permian strata in Culberson and Pecos Counties. Eight operations were located along the Gulf Coast and three in west Texas. Production from the Frasch mines in 1970 increased 5 percent, 81 percent of which (2.8 million long tons) was sold. This sales figure made the state second highest in the nation in the amount of Frasch sulfur sold, though the price had declined because a large amount of cheap sulfur recovered from sour gas had entered the market from western Canada. As a result, several producers closed their Texas Frasch operations, including the Pennzoil United subsidiary, Duval Corporation, which shut down two sulfur facilities in Pecos County and Fort Bend County, while the Texas Gulf Sulphur Company ceased sulfur production in Matagorda County, where it had obtained sulfur since 1919. Also closed was the Rock House plant of Elcor Chemical Corporation in Culberson County, which planned to extract elemental sulfur from gypsum.
In the 1970s, new sources of sulfur developed as the nation sought to reduce air pollution. American Smelting and Refining Company (ASARCO, Incorporated) announced plans for a facility to recover sulfur from sulfur dioxide in smoke emissions at its copper-lead-zinc refinery at El Paso. In 1971 Pan-American Petroleum, a subsidiary of Standard Oil Company of Indiana, changed the name of its Frasch sulfur facility in Galveston County to Amoco Production Company. Sulfur continued to be obtained by extraction from sour gas and oil in Texas, and the state led the nation in shipments of recovered sulfur. In 1975 Texas continued for the fourth year in a row to lead the nation in sulfur production from Frasch mines. Four companies produced sulfur at eight Frasch operations in six Texas counties. Three were in Pecos and Culberson Counties, and five were on the Gulf Coast. Texasgulf completed a new Frasch sulfur mine at Comanche Creek in Pecos County. Although in 1975 production declined nearly 10 percent and sales dropped below the previous year's volume, the price per ton rose sharply; 82 percent of the year's output was sold. The value increased for both Frasch and recovered sulfur. Recovered sulfur production took place at fifty operations in twenty-nine Texas counties that year. The output totaled 801,408 long tons, representing a decrease of 6 percent from the previous year. Total value from sales, however, rose by more than 47 percent, as the average price per long ton increased nearly 60 percent from $22.93 in 1974 to $36.51 in 1975.
In 1980 the Duval Corporation continued to recover Frasch sulfur at its Culberson Mine. Late that year the company also began Frasch production at a new Phillips Ranch operation, also in Culberson County. Farmland Industries in Pecos County, Jefferson Lake Sulphur Company in Fort Bend County, and Texasgulf in Liberty, Pecos, and Wharton counties all mined Frasch sulfur in this period. Recovered sulfur was also extracted from natural gas and crude oil at fifty-nine operations in thirty-three counties. More than a third of the recovered sulfur was produced in Harris County; Harris, Jefferson, and Van Zandt counties contributed more than half the total. Frasch sulfur output in Texas increased by 4.7 percent, and recovered sulfur increased by 2.8 percent. Stocks of total sulfur were depleted by approximately 26 percent. The average price per metric ton rose in 1980 from $90 to $114. In 1990 the overall output of recovered sulfur totaled 3.9 million metric tons valued at $142 million. Pennzoil Sulfur Company and Texasgulf Incorporated, with operations in Culberson, Pecos, and Wharton counties, produced 2.3 million metric tons of Frasch sulfur, a decline from the previous year of 106,000 metric tons. The value declined 17 percent. Plans were made to close the Texasgulf mine by the mid-1990s as it neared depletion. In 1990, however, refineries in seventeen Texas counties recovered 1.6 million metric tons of sulfur. In natural gas and petroleum refining, part of the sulfur in the refinery stream was converted to hydrogen sulfide, then converted to elemental sulfur by the Claus process. Operations included those of Exxon Chemical Americas, Smackover Shell Limited, and Texaco Producing, Incorporated. See also MINERAL RESOURCES, OIL AND GAS INDUSTRY.