Future effective dates beyond the approved or proposed attainment date should not be allowed unless the related emissions reductions are not needed for attainment. Also, the regulation should specify the important dates required of any compliance schedule which is required to be submitted by the source to the state. If changed circumstances affect an emission limit or other requirement, the effect of changed conditions should be clearly specified. However, you should not approve state regulations which tie the applicability of VOC control requirements to the nonattainment status of the area and allow for automatic nullification of the regulations if the area is redesignated to an attainment status. The regulation must be sufficiently specific so that a source is fairly on notice as to the standard it must meet.
Some federal regulations are inappropriate for adoption by reference.
For example, a state intending to enforce PSD regulations adopted by reference must adopt 40 C.F.R. 52.21, not 40 C.F.R. 51.166, as only the former is written in a form imposing obligations on permit applicants. Even then, changes may have to be made to take into account the difference between the State's situation and EPA's. Some states have attempted to provide particular VOC sources with relaxation's of compliance limits in return for improvements in the efficiency with which the sources use the pollutant producing material. Any rules allowing transfer efficiency to be used in determining compliance must be explicit as to when and under what circumstances a source may use improved transfer efficiency as a substitute for meeting the SIP limit. Also, such provisions may not simply reference the NSPS auto coating tables for the transfer efficiency.