40 CFR §1068.315

1. (a)National security exemption. You may import an engine or piece of equipment under the national security exemption in § 1068.225.
2. (b)Manufacturer-owned engine/equipment exemption. You may import manufacturer-owned engines/equipment, as described in § 1068.215.
3. (c)Replacement engine exemption. You may import a nonconforming replacement engine as described in § 1068.240. To use this exemption, you must be a certificate holder for a family we regulate under the same part as the replacement engine.
4. (d)Extraordinary circumstances exemption. You may import a nonconforming engine or piece of equipment if we grant hardship relief as described in § 1068.245.
5. (e)Small-volume manufacturer exemption. You may import a nonconforming engine or piece of equipment if we grant hardship relief for a small-volume manufacturer, as described in § 1068.250.
6. (f)Equipment-manufacturer hardship exemption. You may import a nonconforming engine if we grant an exemption for the transition to new or revised emission standards, as described in § 1068.255.
7. (g)[Reserved]
8. (h)Identical configuration exemption. Unless specified otherwise in the standard-setting part, you may import nonconforming engines/equipment if they are identical in all material respects to certified engines/equipment produced by the same manufacturer, subject to the following provisions:
   1. (1)You must meet all the following criteria:
      1. (i)You have owned the engines/equipment for at least six months.
      2. (ii)You agree not to sell, lease, donate, trade, or otherwise transfer ownership of the engines/equipment for at least five years. The only acceptable way to dispose of the engines/equipment during this five-year period is to destroy or export them.
      3. (iii)You use data or evidence sufficient to show that the engines/equipment are in a configuration that is identical in all material respects to engines/equipment the original manufacturer has certified to meet emission standards that apply at the time the manufacturer finished assembling or modifying the engines/equipment in question. If you modify the engines/equipment to make them identical, you must completely follow the original manufacturer's written instructions.
   2. (2)We will tell you in writing if we find the information insufficient to show that the engines/equipment are eligible for the identical configuration exemption. We will then not consider your request further until you address our concerns.