is an extremely rare, benign form of pneumoconiosis that causes little or no overgrowth, hardening, and/or scarring of the tissue in the lung (fibrosis). Pneumoconiosis is caused by accumulation of inhaled particles and involves a reaction of tissue in the lung. In the case of baritosis, the inhaled particles are made up of barium sulfate and is well described in workers who crush and grind compounds containing barium, a mineral found in paints, paper, ceramics, glass, rubber, electronic components, and in drilling muds in oil and gas exploration. Baritosis is typically characterized by a mixture of very fine punctate and annular (ring-like) lesions and some slightly larger nodular lesions in the lung. The condition generally appears 1 to 2 years after exposure, does not affect the function of the lung, and appears to go away without treatment after exposure stops. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.