Gray powder or metal, odorless. There is a risk of asthma crisis if cobalt powder is inhaled. It can be a cause of skin, ocular and respiratory tract irritation. Acetate, sulfate, trioxide and nitrate cobalt salts are potentially carcinogenic. Mandatory measures to prevent inhalation (room air extraction and respiratory protection) and ingestion (avoid eating, drinking or smoking in the work place). The industry must ensure a Threshold Limit Value (TLV) (TWA as well) less than 0.05 mg/m3 (cobalt salts less than 0.002 mg/m3). Biological Exposition Index (BEI) on the last labor week day: 15 micrograms/L in the urine, 1 microgram/L in the blood. Benefits of breastfeeding are largely more important than risk related to the presence of mild level environment pollutants in human milk, in many instances, they are at lower content than those found in cow’s milk or other foods. (Codex alimentarius FAO-WHO).