Is there any harm with cooking in a rusty pot?

The National Institute of Occupational Safety and Health (NiOSH) indicates that rust is not toxic. The only problem noted is benign pneumoconiOSis with X-ray shadows indistinguishable from fibrotic pneumoconiOSis (siderosis) when inhaled. If eaten the acid in the digestive processes will convert rust to iron needed for blood formation or excrete the excess.