The EPA is partially approving and partially disapproving the East Helena Lead (Pb) State Implementation Plan (SIP) revisions submitted by the Governor of Montana on August 16, 1995, July 2, 1996, and October 20, 1998. The EPA is partially approving and partially disapproving these SIP revisions because, while they strengthen the SIP, they also do not fully meet the Act's provisions regarding plan requirements for nonattainment areas. The intended effect of this action is to make federally enforceable those provisions that EPA is partially approving, and not make federally enforceable those provisions that EPA is partially disapproving. The EPA is taking this action under sections 110, 179, and 301 of the Clean Air Act (Act).