Section 52.1375 - Control strategy: Lead(a) Determination-EPA has determined that the East Helena Lead nonattainment area has attained the lead national ambient air quality standards through calendar year 1999. This determination is based on air quality data currently in the AIRS database (as of the date of our determination, June 18, 2001).(b) Redesignation to attainment-The EPA has determined that the East Helena lead (Pb) nonattainment area has met the criteria under CAA section 107(d)(3)(E) for redesignation from nonattainment to attainment for the 1978 Pb NAAQS. The EPA is therefore redesignating the East Helena 1978 Pb nonattainment area to attainment.(c) Maintenance plan approval-The EPA is approving the maintenance plan for the East Helena nonattainment area for the 1978 Pb NAAQS submitted by the State of Montana on October 28, 2018. 84 FR 47897 , Sept. 11, 2019