The studies of the association of barium and cardiovascular endpoints or blood pressure in humans are very limited methodologically, and do not to provide reliable evidence to establish the RfD. The effect of chronic barium exposure on cardiovascular or renal parameters in humans is unknown. Other available studies of barium exposure in humans, including case reports of acute intoxications, the study of Yoshinaga et al. on the barium concentration in the ribs of autopsy patients with different conditions, and the studies of inhaled barium (see the Toxicological review of barium and compounds for a detailed summary of all these studies) do not provide information useful to derive the oral RfD.