Thorium dioxide

Processing thorium ores (monazite); making/using thoriated tungsten welding rods; refractory ceramics and catalysts; legacy medical use (Thorotrast) [1][2][4].

Breathing dust/fumes at work; ingesting or inhaling contaminated soil or dust near facilities or waste sites; past medical injections of Thorotrast [1][4].

Known human carcinogen; linked to liver cancers (angiosarcoma, cholangiocarcinoma), leukemia, and radiation injury to liver, spleen, and bone [2][3][1].

Workers in thorium mining/processing, welding, or ceramics that handle ThO2; people who received Thorotrast; communities near contaminated sites [1][4][2].

At work, use local exhaust, wet methods, closed handling, and appropriate respirators; substitute non‑thoriated electrodes when possible; follow radiation safety and waste rules. At home/near sites, avoid dust, wash hands, keep children off contaminated soil, and follow health advisories [1][4].