Sec. 3.
(d) Following any exceedance of the twenty-four (24) hour ambient air quality standard for PM10 and upon completion of the culpability study described in section 3 of this rule, the department shall notify the source or sources that the department has identified as likely to have caused or contributed to the exceedance and request that the source or sources voluntarily implement controls that will reduce the source's PM10 emissions by fifteen percent (15%). The department's notification shall include the results of the culpability study. The department shall request a reduction less than fifteen percent (15%) if the culpability study demonstrates that a lesser percent reduction would ensure that no further exceedance will occur under the same circumstances. If the department determines that a single facility at a source caused or significantly contributed to the exceedance, then the department will request that voluntary reductions be implemented only at the specific facility. *These documents are incorporated by reference and are available from U.S. EPA, Office of Air Quality Planning and Standards, Research Triangle Park, North Carolina 27711 or are available for review and copying at the Department of Environmental Management, Office of Air Quality, Indiana Government Center-North, Tenth Floor, 100 North Senate Avenue, Indianapolis, Indiana 46204.