Section 33.42. Secondary containment structures; standards.

  A secondary containment structure required under s. ATCP 33.40 (1) shall comply with all of the following requirements:

(1)   Construction standards; general.

(a) A secondary containment structure shall take one of the forms authorized in s. ATCP 33.44 .

(b) A secondary containment structure shall be designed, constructed and maintained to contain potential discharges of liquid fertilizer or pesticide from storage containers and appurtenances located within the structure.

(c) A secondary containment structure shall have the capacity required in sub. (2) . An operator shall notify the department at least 7 business days before installing an additional storage container in a secondary containment structure, or replacing an existing storage container in a secondary containment structure with a larger storage container.

(d) A secondary containment structure shall comply with applicable wall height requirements in sub. (3) .

(e) A secondary containment structure shall be designed, constructed and maintained to do all of the following:

1. Withstand the full hydrostatic head of any liquid discharged within the structure.

2. Prevent liquid in the structure from moving to groundwater or other waters of the state.

(f) A secondary containment structure shall have a coefficient of permeability of not more than 1x10 -6 cm/sec.

(g) A secondary containment structure shall be designed to withstand the filled weight of all storage containers, appurtenances, pumps and equipment that may be used or located within it.

(h) A secondary containment structure may not have any opening through which precipitation or other liquids may drain from the structure. This paragraph does not apply to any of the following:

1. A tank-in-tank that complies with s. ATCP 33.44 (9) .

2. A bladder tank that complies with s. ATCP 33.44 (10) .

3. An opening for a pipe that extends through the wall of a secondary containment structure constructed prior to November 1, 2006, provided that the operator complies with s. ATCP 33.20 (2) (d) 2. or the secondary containment structure has adequate containment capacity as required under sub. (2) below the level of the opening.

(2)   Capacity.

(a) The capacity of a secondary containment structure, including all portions of the structure to which a liquid may freely flow, shall be at least equal to the sum of all the following:

1. One hundred and twenty five percent of the capacity of the largest storage container in the secondary containment structure if the secondary containment structure is not fully enclosed in a building, or 110% of the capacity of the largest storage container in the secondary containment structure if the secondary containment structure is enclosed in a building.

2. The total volume of discharged liquid that would be displaced by the submerged portions of all other storage containers, fixtures and materials located within the secondary containment structure, if the structure were filled to capacity with discharged liquid.

(b) Paragraph (a) does not apply to a bladder tank that complies with s. ATCP 33.44 (10) .

(3)   Wall height.

(a) Except as provided in pars. (b) to (d) , a secondary containment structure shall have walls at least 4 inches high but not more than 4 feet high, measured from the interior floor of the secondary containment structure.

(b) Paragraph (a) does not apply to an earthen-lined structure that complies with s. ATCP 33.44 (6) , a tank-in-tank that complies with s. ATCP 33.44 (9) , or a bladder tank that complies with s. ATCP 33.44 (10) .

(c) A secondary containment structure that was in use prior to November 1, 2006 may have walls more than 4 feet high if the structure provides safe access to storage containers and appurtenances, and a safe exit in the event of a discharge.

(d) A secondary containment structure that was in use prior to November 1, 2006 may have walls less than 4 inches high, provided that the structure meets the capacity requirements in sub. (2) .

(4)   Storage container location.

(a) Except as provided in par. (b) , all storage containers in a secondary containment structure shall be located at least 24 inches from the walls of the structure and at least 24 inches from each other.

(b) Paragraph (a) does not apply to any of the following:

1. Storage containers installed in a secondary containment structure constructed prior to November 1, 2006.

2. Bladder tanks.

3. Mini-bulk containers.

(5)   Inspection and maintenance. An operator shall do all of the following:

(a) Routinely inspect and maintain a secondary containment structure to ensure compliance with this subchapter.

(b) Repair a secondary containment structure, when necessary, according to good engineering practice and manufacturer specifications.

(c) Remove a secondary containment structure if the operator cannot maintain it in compliance with this subchapter, or if corrective action is needed to remove contamination from beneath the structure. An operator shall remove a leaking secondary containment structure unless the structure is repaired and remains liquid-tight for at least 2 years after the date of repair.

(6)   Liquid pesticide stored with other materials.

(a) Except as provided in par. (b) , only the following materials may be stored in the same secondary containment structure with liquid bulk pesticide:

1. Other liquid pesticides.

2. Pesticide diluting agents.

3. Pesticide rinsate.

4. Empty pesticide containers.

5. Recovered pesticide discharges.

(b) Liquid bulk pesticide may be stored in the same secondary containment structure with bulk fertilizer or dry bulk pesticide if either of the following applies:

1. The secondary containment structure contains only mini-bulk or mobile storage containers, or both.

2. The secondary containment structure is located within a fully enclosed building.

CR 05-108 : cr. Register October 2006 No. 610 , eff. 11-1-06.