You may think that submitting a No Exposure Certification is the last step in complying with stormwater regulations at your industrial facility. And why not? If your facility's materials and operations are not exposed to stormwater at the time you submit the certification and no limitations apply, you qualify for the No Exposure Exclusion. What you may not have realized that you must maintain no exposure conditions for the duration of the certification.

The intent of the No Exposure Exclusion is to provide industrial facilities regulated under the National Pollutant Discharge Elimination (NPDES) program, whose industrial activities and materials are completely sheltered, with a simplified method for complying with the Clean Water Act. Facilities that qualify for the No Exposure Exclusion are not required to be covered by a stormwater permit.

Here are the most common reasons facility owners and operators believed they qualified for the No Exposure Exclusion, but were soon disqualified and lost their certification, and some guidance on how to address disqualification situations.

Non-resistant shelters. Storm-resistant shelters include completely roofed and walled structures and can include top-cover-only structures, which do not require side coverings as long as the stored material is not subject to any stormwater contact. Contact can be avoided through the use of berms around the area where the activities and materials are stored or sloping the ground in a way that would prevent run-off of potential spills.

Containers that are properly covered or lidded, large roll-off type bins, and dumpsters can qualify as storm resistant shelter as long as they:

• Are not leaking or deteriorating
• Have bottom drain plugs to prevent leaks
• Have sturdy covers and lids that won’t break down in sunlight or allow stormwater to enter

Spills and leaks in transfer areas. Disqualification may occur if there is a lack of proper transfer in fueling areas. “Topping off” fuel tanks and leaking storage tanks are considered fuel spills.

To properly maintain on-site fueling stations to maintain no exposure compliance, make sure to comply with the following:

• Dry cleanup methods for spills are implemented rather than procedures for washing the areas down with water or liquid cleaning solutions.
• The fueling area is under a storm-resistant, protective canopy or roof.
• The fueling area is bermed to keep spills in and surrounding stormwater flows out.

Spills and leaks during loading/unloading. Spills and leaks can occur during loading and unloading of significant materials. Significant materials include material handling equipment; industrial machinery; raw materials; intermediate products, by-products, and final products; or waste products.

Loading and unloading operations can be properly managed by conducting them within a storm-resistant shelter and following these guidelines:

• Make sure trailer ends at docks are enclosed with overhangs or door skirts.
• Raise the loading area more than 2 feet off the ground surface to prevent stormwater run-on, and place loading areas under facility roofs.
• Conduct material transfers on impervious pads to enable easy collection of spilled materials.

For more information on the No Exposure Exclusion, see the EPA’s Guidance Manual for Conditional Exclusion from Stormwater Permitting.