40 CFR § 442.1 - General applicability.
(a) As defined more specifically in each subpart, and except for discharges specified in paragraph (b) of this section, this part applies to discharges resulting from cleaning the interior of tanks used to transport chemical, petroleum or food grade cargos. This part does not apply to facilities that clean only the exteriors of transportation equipment. Operations which may be subject to this part typically are reported under a wide variety of Standard Industrial Classification (SIC) codes. Several of the most common SIC codes include: SIC 7699, SIC 4741, or SIC 4491 (1987 SIC Manual).
(b) This part is not applicable to the following discharges:
(1) Wastewaters associated with tank cleanings operated in conjunction with other industrial, commercial, or Publicly Owned Treatment Works (POTW) operations, provided that the cleaning is limited to tanks that previously contained raw materials, by-products, or finished products that are associated with the facility's on-site processes.
(2) Wastewaters resulting from cleaning the interiors of drums, intermediate bulk containers, or closed-top hoppers.
(3) Wastewater from a facility that discharges less than 100,000 gallons per year of transportation equipment cleaning process wastewater.