(a)

1. (1) The emissions limitations contained within this part and applicable permits are for the purpose of assuring the attainment and maintenance of the national ambient air quality standards and have been established within the framework of information presently available to the Division of Environmental Quality.

2. (2) As additional and more precise information becomes available, the emission limitations and reporting procedures of this subpart may be amended as described below:

   1. (A)

(i) More restrictive limitations to protect the national ambient air quality standards.

1. (ii) In accordance with the provisions of the federal Clean Air Act, as amended, and the federal regulations promulgated pursuant to the Clean Air Act, as amended, the emission limitations and reporting procedures of this subpart or any applicable permits may be further amended and made more restrictive where the Director of the Division of Environmental Quality finds more restrictive measures are necessary to assure maintenance of the national ambient air quality standards; and

   1. (B)

      1. (i) Less restrictive limitations.
      2. (ii) Any person subject to the emission limitations contained in this part or in a permit may petition the director for a less stringent limitation on the grounds that the existing limitation cannot be met when considering physical, economical, or technological constraints.
      3. (iii) In no case shall the director approve a less stringent limitation if it would cause a violation of the national ambient air quality standards.
      4. (iv) The director shall not approve a less stringent limitation if it violates a federal emission standard or regulation, unless approved according to applicable federal regulations.

2. (3) The director shall take into account the following factors when making such determinations:

   1. (A) The process, fuels, and raw materials available and to be employed in the facility involved;
   2. (B) The engineering aspects of the application of various types of control techniques that have been adequately demonstrated;
   3. (C) Process and fuel changes;
   4. (D) The respective costs of the application of all such control techniques, process changes, alternative fuels, etc.; and
   5. (E) Locational and siting considerations.

(b) In any enforcement proceeding, the permittee seeking to establish the occurrence of an emergency has the burden of proof.

1. (c) This provision is in addition to any emergency or upset provision contained in any applicable requirement.