Sulphur (French: Soufre) is a city in Calcasieu Parish, Louisiana, United States. The population was 20,410 at the 2010 census. Sulphur is part of the Lake Charles Metropolitan Statistical Area.
Sulphur is named for the sulfur mines that were operated in the area in the 1900s. In 1867, Professor Eugene W. Hilgard, an experienced geologist who was prospecting for oil and other minerals, conducted exploratory borings in Calcasieu Parish, Louisiana and discovered sulfur in the caprock of a salt dome. However, the sulfur was beneath several hundred feet of muck and quicksand containing deadly hydrogen sulfide gas, which made mining extremely hazardous. Repeated unsuccessful attempts to sink conventional mining shafts in the 1870s and 1880s resulted in the loss of many lives.
In 1890, the German immigrant Herman Frasch invented and patented the Frasch Process of mining sulfur, using concentric pipes to pump superheated water into the ground, liquefy the mineral, and force the liquid to the surface with compressed air. The first molten sulfur was brought to the surface on Christmas Eve of 1894. Sulfur soon began to be mined on an industrial scale, with the molten mineral allowed to solidify and dry in enormous vats 100 by 400 feet, then blasted and hauled by rail to the Sabine River for shipment.