The Cornforth reagent is very toxic to aquatic life and may cause long-term damage to the environment if released in large amounts. It irritates skin and mucous membranes and may induce allergic reactions; it is carcinogenic. The maximum allowable concentration varies between 0.01 and 0.1 mg·m in air depending on the country. Because it contains hexavalent chromium, it is a suspected carcinogen, and as a strong oxidant, pyridinium dichromate promotes fires, releasing carbon monoxide, carbon dioxide and toxic metal smoke. The fire can be extinguished by water or CO.