Molybdenum trioxide

Produced when roasting molybdenum ore and during refining; used in steelmaking, catalysts, pigments, glass, and ceramics; released as dust/fume in high‑temperature processes [1].

Breathing workplace dust or welding fumes; living near mines/smelters or metal-processing plants; small amounts may be in food and drinking water, especially near mining areas [1].

Short‑term inhalation can cause nose, throat, and eye irritation; long‑term high intake may cause gout‑like symptoms from copper imbalance; IARC classifies molybdenum trioxide as possibly carcinogenic to humans (Group 2B) [1][2].

Miners, smelter and furnace operators, welders, and workers making catalysts, pigments, or Mo‑alloy parts; people with kidney disease may be more sensitive; nearby residents if dust controls are poor [1][3].

At work, use ventilation, wet methods, and NIOSH‑approved respirators; follow exposure limits and hygiene (wash hands, change clothes); at home, reduce dust, follow product safety guidance, and test private wells if near mining [1][3].