40 CFR §279.66

1. (a)Certification. Before a burner accepts the first shipment of off-specification used oil fuel from a generator, transporter, or processor/re-refiner, the burner must provide to the generator, transporter, or processor/re-refiner a one-time written and signed notice certifying that:
   1. (1)The burner has notified EPA stating the location and general description of his used oil management activities; and
   2. (2)The burner will burn the used oil only in an industrial furnace or boiler identified in § 279.61(a).
2. (b)Certification retention. The certification described in paragraph (a) of this section must be maintained for three years from the date the burner last receives shipment of off-specification used oil from that generator, transporter, or processor/re-refiner.