Skip to main content

Facilities that shelter all significant materials and activities indoors or within a storm-resistant shelter can apply for "no exposure." Efforts to minimize your operational exposure to stormwater can help you save money and time, and protect our surface and groundwater resources. Certifying as no exposure lets you avoid the requirements of the industrial stormwater permit, including:

  • creating a stormwater pollution prevention plan.
  • paying application and annual fees.
  • submitting annual reports.
  • monitoring.

Storm-resistant shelters

Storm-resistant shelters include completely roofed and walled structures. Roof-only structures may qualify provided the material under the structure is not otherwise subject to any run-on and subsequent runoff of stormwater, such as areas with berms or inward sloping that prevent spills from running off site.

Outdoor significant materials

No exposure means that rain, snow, and runoff never come in contact with "significant materials" or industrial activities. Significant materials and activities can be found in raw materials, intermediate products, byproducts, final products, waste prod­ucts, material-handling operations, and manufacturing equipment. Pollutants of concern include metals, oil and grease, organics, sediments, nutrients, and other chemicals. Materials are considered significant if they contain pollutants that could be transferred to stormwater.

Significant materials

  • fuels, solvents, coolants, lubricants and cleaners
  • raw, intermediate, and final products
  • metallic materials
  • chemicals
  • wastes and scrap materials
  • hazardous materials/wastes
  • processing or production operations
  • machining fluids
  • dust or residuals
  • fueling stations
  • above-ground tanks for liquid storage

Industrial activities

  • outdoor storage, particularly for raw materials, by-products, and finished products
  • outside manufacturing
  • vehicle and equipment washing, maintenance and storage areas
  • loading and unloading operations
  • fueling of vehicles and equipment
  • other substance transfer areas
  • outdoor manufacturing or processing
  • significant dust or particulate generation
  • onsite waste disposal
  • grinding, cutting, degreasing, buffing, and brazing
  • industrial waste management areas (landfills, waste piles, treatment plants, disposal areas)

Prevent exposure to stormwater

The following measures can help you prevent exposing pollutants to stormwater. See Step 4 for more information about stormwater control measures:

  • move significant materials and activities under cover
  • increase waste pickup frequency
  • optimize maintenance practices
  • control spills and leaks
  • manage wastes
  • optimize operations

Common violations at no exposure facilities

Not all facilities who certify for no exposure can qualify. Here are common sources of exposure at facilities attempting to certify for no exposure:

  • Open/unplugged dumpsters that can leak when stormwater gets in.
  • Storing significant materials outdoors, such as corrodible metals, used appliances, etc.
  • Industrial activities conducted outdoors, such as mixing of wastes, loading/unloading of products, etc.
  • Fueling of vehicles and equipment outdoors
  • Dust and particulates visible in the air or deposits on the ground.
  • Pollutants potentially mobilized by wind; materials sheltered from precipitation can still be deemed exposed if the materials can be windblown.
  • Metal processing facilities with uncovered, outside bins that contain scrap metal
  • Trash compactors with hydraulic leaks or contents falling out of equipment seams, or exposure from loading or unloading
  • “Bag houses” or other particulate matter collection devices that release particulate matter