(b) For a modification with a project emission potential which, when added to all emissions excluded under section 231-4.1(b)(42)(i)(c) of this Part and which is less than 50 percent of the applicable significant project threshold in table 3, table 4 or table 6 of Subpart 231-13 of this Part, the facility owner or operator, in addition to complying with any requirements under Part 201 of this Title, must maintain the following information for a minimum of five years:

1. (1) a description of the modification;
2. (2) an identification of each new or modified emission source(s) including the associated processes and emission unit;
3. (3) the calculation of the project emission potential for each modified emission source(s) including supporting documentation; and

4. (4) the date the modification commenced operation.

   These recordkeeping requirements apply to exempt and trivial activities but do not affect their exempt or trivial permitting status under Subpart 201-3 of this Title.

(c) For a modification with a project emission potential which, when added to any emissions excluded in accordance with section 231-4.1(b)(42)(i)(c) of this Part, equals or exceeds 50 percent of the applicable significant project threshold in table 3, table 4 or table 6 of Subpart 231-13 of this Part and the project emission potential is less than the applicable significant project threshold, the facility owner or operator must submit an application to modify the facility permit under the minor permit provisions of Subpart 201-6 of this Title, and must:

1. (1) maintain the following information for a minimum of five years:

   1. (i) a description of the modification;
   2. (ii) an identification of each new or modified emission source(s) including the associated processes and emission unit;
   3. (iii) the calculation of the project emission potential for each modified emission source(s) including supporting documentation; and
   4. (iv) the date the modification commenced operation;
2. (2) monitor the emissions of each regulated NSR contaminant from the emission source(s) that will increase as a result of the modification, and calculate and maintain a record of the annual emissions, in tons per year on a calendar year basis, for a period of five years following resumption of regular operations after the modification, or for a period of 10 years following resumption of regular operations after the change if the modification increases the design capacity of or potential to emit the regulated NSR contaminant at such emission source(s). The calculation of actual emissions must use the same methodology that was used in the application for the project; and

3. (3) submit a report to the department within 30 days after the end of each year during which records must be generated in accordance with paragraph (2) of this subdivision. The report must contain:

   1. (i) the name, address, and telephone number of the major facility;
   2. (ii) the annual emissions as calculated pursuant to paragraph (2) of this subdivision; and
   3. (iii) a comparison of actual annual emissions to the projected actual emissions and, if applicable, an explanation as to why the actual annual emissions exceeded the projected actual emissions.