In the case of diesel-water fuel emulsion at least 14 percent of which is water and with respect to which the emulsion additive is registered by a United States manufacturer with the Environmental Protection Agency pursuant to section 211 of the Clean Air Act (as in effect on March 31, 2003), subparagraph (A)(iii) shall be applied by substituting “19.7 cents” for “24.3 cents”. The preceding sentence shall not apply to the removal, sale, or use of diesel-water fuel emulsion unless the person so removing, selling, or using such fuel is registered under section
4101.