Since titanium dioxide accounts for roughly 70 percent of the pigment used commercially on a global scale, there have been concerns raised over its toxicity in the workplace. In response, a number of global agencies have advised manufacturers to update material safety data sheets and occupational hazard training programs based on current safety reviews. For example, the International Agency for Research on Cancer (IARC) has now classified this substance a potential carcinogen based on the rate of incidence of respiratory tract cancer in rats after prolonged inhalation of titanium dioxide dust particles. However, as a food additive in minute quantities, this material is considered safe for human consumption.