Today, EPA is rescinding its prior findings that the 1-hour ozone national ambient air quality standard (NAAQS) and the accompanying designations and classifications no longer apply in certain areas. As part of a transition to a new, more protective 8-hour ozone standard (promulgated in July 1997), in 1998 and 1999, EPA took final action determining that the 1-hour standard would no longer apply in almost 3,000 counties. Now, however, the public health protection that would be afforded by the 8-hour ozone standard is being delayed because continued litigation regarding the 8-hour ozone standard has created uncertainty regarding when and whether EPA may be able to fully implement that standard. It is important to have a fully enforceable Federal ozone standard to help protect people from the respiratory and other harmful effects of ozone pollution. Under this final rule, the designations and classifications that previously applied in such areas with respect to the 1-hour standard would also be reinstated. This rule will become effective in 90 days for most areas, and will become applicable in 180 days for areas with clean air quality data that had a nonattainment designation when the 1-hour standard was revoked. Furthermore, today EPA is taking final action to amend 40 CFR 50.9(b) to provide by rule that the 1-hour ozone standard will continue to apply to all areas notwithstanding promulgation of the 8-hour ozone standard; and that after the 8-hour standard has become fully enforceable under part D of title I of the Clean Air Act (CAA) and is no longer subject to further legal challenge, the 1-hour standard set forth in section 50.9(a) will no longer apply to an area once EPA determines that the area has air quality meeting the 1-hour standard.