40 CFR §147.2927

1. (a)Permits may be modified for the following causes only (with the exceptions listed in paragraph (b) of this section regarding minor modifications):
   1. (1)There are substantial changes to the facility or activity which occurred after permit issuance that justify revised or additional permit conditions.
   2. (2)The Regional Administrator has received information (e.g., from monitoring reports, inspections) which warrants a modified permit.
   3. (3)The regulations or standards on which the permit was based have changed.
   4. (4)The Regional Administrator has received notice of a proposed permit transfer.
   5. (5)An interested person requests in writing that a permit be modified, and the Regional Administrator determines that cause for modification exists.
   6. (6)Cause exists for termination under § 147.2928, but the Regional Administrator determines that permit modification is appropriate.
2. (b)Minor modifications.
   1. (1)Minor modifications do not require that the procedures listed in paragraph (c) of this section be followed.
   2. (2)Minor modifications consist of:
      1. (i)Correcting typographical errors;
      2. (ii)Requiring more frequent monitoring or reporting;
      3. (iii)Changing ownership or operational control (see § 147.2926, Permit Transfers); or
      4. (iv)Changing quantities or types of injected fluids, provided:
         1. (A)The facility can operate within conditions of permit;
         2. (B)The facility classification would not change.
3. (c)Modification procedures.
   1. (1)A draft permit shall be prepared with proposed modifications.
   2. (2)The draft permit shall follow the general permitting procedures (i.e., public comment period, etc.) before a final decision is made.
   3. (3)Only the changed conditions shall be addressed in the draft permit or public review.