1998 Revisions to the Carbon Monoxide Maintenance Plan Categories Topics Air Quality Plans Programs California State Implementation Plans Tipo Information On October 22, 1998, CARB revised the SIP to incorporate the effects of the recent CARB action to remove the wintertime oxygen requirement for gasoline in certain areas.CARB DocumentsNotice of Public Hearing1998 Plan (October 6, 1998) Related Resources Mobile Source Strategy 2023 Eastern Kern Reasonably Available Control Technology SIP California Smog Check Contingency Measure