Industrial Uses
Adding cobalt sulfate to nickel-plating baths makes treated metals brighter, harder, more ductile and smoother. The mineral also produces red tints in pottery and porcelain glazes and helps to dry and fix inks on lithographic prints.
Food and Drug Uses
Brewers once used cobalt sulfate to prolong the life of beer foam, and ranchers have dosed livestock with cobalt sulfate or used fertilizer enriched with cobalt sulfate to ensure their animals get enough of the trace mineral needed to produce vitamin B12. Also, until recently, cobalt sulfate had a therapeutic role in treating certain forms of anemia.
Health Risks
Long-term or repeated eye and skin exposure to cobalt sulfate can cause irritation, a rash and redness that will fade when such exposures end. Inhaling cobalt sulfate dust over an extended period, which is a possibility in manufacturing settings where the powdered mineral is used, can lead to poisoning and might cause cancer. The Eleventh Report on Carcinogens from the National Institute for Environmental Health Sciences identifies cobalt sulfate as a likely carcinogen but notes that the mineral's role in causing cancer is difficult to define because most individuals who work with cobalt sulfate also work with other heavy metals and cancer-causing chemicals.
Cobalt Sulfate Poisoning
Acute cobalt sulfate poison---the rapid inhalation of too much dust---can cause coughing, nausea, shortness of breath and vomiting but will not be life-threatening. Poisoning that results from chronic inhalation of cobalt sulfate causes irreversible blood thickening, enlarged heart (cardiomyopathy), pain and tingling (neuropathy), and thyroid dysfunction.
Regulations
Federal Clean Air Act regulations list cobalt sulfate as a hazardous air pollutant, and companies must report spills and releases of cobalt compounds to federal and local emergency response agencies. Further, the U.S. Food and Drug Administration prohibits the use of cobalt sulfate in beverages, foods and medications for humans.