Cobalt is an essential element for health in animals in minute amounts as a component of vitamin B12.

[1] Soluble cobalt(II) salts are "possibly carcinogenic to humans" (IARC Group 2B Agents).

In August 1965, a person presented to a hospital in Quebec City with symptoms suggestive of alcoholic cardiomyopathy.

[4] Epidemiological studies found that Dow had been adding cobalt sulfate to the beer for foam stability since July 1965 and that the concentration added in the Quebec city brewery was ten times that of the same beer brewed in Montreal where there were no reported cases.

[5][6] A 1972 paper noted that several dozen cases were also identified over a similar time period in Omaha, Nebraska; Minneapolis, Minnesota; and Belgium.