40 CFR §279.61

1. (a)Off-specification used oil fuel may be burned for energy recovery in only the following devices:
   1. (1)Industrial furnaces identified in § 260.10 of this chapter;
   2. (2)Boilers, as defined in § 260.10 of this chapter, that are identified as follows:
      1. (i)Industrial boilers located on the site of a facility engaged in a manufacturing process where substances are transformed into new products, including the component parts of products, by mechanical or chemical processes;
      2. (ii)Utility boilers used to produce electric power, steam, heated or cooled air, or other gases or fluids for sale; or
      3. (iii)Used oil-fired space heaters provided that the burner meets the provisions of § 279.23; or
   3. (3)Hazardous waste incinerators subject to regulation under subpart O of parts 264 or 265 of this chapter.
2. (b)
   1. (1)With the following exception, used oil burners may not process used oil unless they also comply with the requirements of subpart F of this part.
   2. (2)Used oil burners may aggregate off-specification used oil with virgin oil or on-specification used oil for purposes of burning, but may not aggregate for purposes of producing on-specification used oil.