Radioactive substance
(8) The definition of radioactive substance in section 2(m) of the act (restated in paragraph (b)(11) of this section) is supplemented by the following: Radioactive substance means a substance which, because of nuclear instability, emits electromagnetic and/or particulate radiation capable of producing ions in its passage through matter. Source materials, special nuclear material, and byproduct materials described in section 2(f)(3) of the act are exempt.