(1) A provision or endorsement found in or attached to virtually all property policies (other than the specialty policies designed to cover loss as a result of nuclear radiation). Eliminates coverage for loss or damage from nuclear reaction or radiation or radioactive contamination, except that ensuing fire is explicitly covered. (2) A provision or endorsement found in or attached to virtually all commercial lines liability policies. The standard broad form nuclear energy exclusion most often attached to liability policies (IL 00 21) precludes coverage only for liability insured under a nuclear energy liability policy or for which indemnity is available from the U.S. government. The exclusion does not normally apply to liability arising from radioactive isotopes, the most common commercially used nuclear materials.