Q) What are “industrial materials” for No Exposure Certification (NEC)? Is it anything that has been in your building?

A) No. Industrial materials are materials used, handled, stored, manufactured, processed, or disposed of in an industrial activity that could be exposed to precipitation.

This includes raw materials, fuels, oils, chemicals, waste materials, and products related to industrial operations.

It does not include normal office contents (desks, paper, electronics) or sealed building contents never exposed outdoors.

Citations:

• 40 CFR §122.26(g) (No Exposure exclusion)
• EPA MSGP, Appendix E – No Exposure Certification, definition of “industrial materials”

Q) How should I handle oil leaks and rainbow sheens from employee vehicles in parking lots?

A) Employee vehicle leaks can trigger stormwater findings. Best practices:

• Document as non‑industrial sources but still address them.
• Implement good housekeeping: absorbent pads, spill kits, regular sweeping.
• Prompt cleanup of sheens.
• Post employee notices encouraging reporting leaks.
• Track repeated issues as minor corrective actions, not permit violations unless persistent.

States generally do not expect elimination of employee vehicles, but reasonable controls are acceptable.

Citations:

• EPA MSGP Part 2.1 (Good Housekeeping & Spill Prevention)
• EPA MSGP Part 3 (Inspections)

Q) Are federal stormwater rules only for EPA‑run states? Can state programs differ?

A) Yes and yes.

• EPA sets minimum federal requirements under the Clean Water Act.
• Authorized states run their own programs and may add more stringent or different requirements.
• States cannot be less protective than EPA rules.

Always follow state permit language first.

Citations:

• Clean Water Act §402(b)
• 40 CFR §123.25 (State program requirements)
• 40 CFR §122.26

Q) What stormwater requirements apply to a trucking company?

A) Trucking terminals typically fall under Transportation Facilities (Sector P) if they:

• Perform vehicle maintenance, fueling, washing, or parts storage outdoors.
  Requirements may include:
• Stormwater permit (MSGP or state equivalent)
• Stormwater Pollution Prevention Plan (SWPPP)
• Inspections, corrective actions, and possibly sampling

Pure office‑only dispatch yards may qualify for No Exposure.

Citations:

• EPA MSGP, Sector P – Transportation Facilities
• 40 CFR §122.26(b)(14)(viii)

Q) What stormwater permit does a city generally fall under?

A) Cities usually operate under multiple permits, including:

• MS4 (Municipal Separate Storm Sewer System) permit for public drainage systems
• Industrial permits for specific facilities (garages, treatment plants, landfills)
  Each facility is evaluated individually.

Citations:

• 40 CFR §122.26(b)(8) (MS4s)
• 40 CFR §122.26(b)(14) (Industrial activities)

Q) What qualifies someone to perform a stormwater inspection?

A) The permit typically requires a “qualified person”, meaning someone who has:

• Stormwater training
• Knowledge of site operations and best management practices (BMPs)
• Ability to identify pollution sources
  
  

Formal certification is usually not required, but training records should exist.

Citations:

• EPA MSGP Part 1.1 (Definitions – “Qualified Personnel”)
• EPA MSGP Part 3.1 (Inspections)

Q) How long after rain starts should samples be taken?

A) Typically within the first 30 minutes of discharge from a qualifying storm event, unless the permit allows otherwise.

Citation:

• EPA MSGP Part 4.1.3 (Sample Collection Procedures)

Q) What if rain occurs during weekends or non‑working hours?

A) Most industrial stormwater permits expect facilities to make reasonable efforts to collect samples during qualifying storm events, including during non‑working hours (e.g., on‑call staff, contractors, or automated samplers).

If sampling is not possible due to documented safety concerns or true infeasibility, permits generally allow an exception. In those cases, you must document:

• Date and time of the storm event
• Specific reason sampling could not be performed
• Any attempts made to sample
• Collection at the next qualifying storm event

Citations:

• EPA MSGP Part 4.1.1 & 4.1.2
• EPA MSGP “Adverse Weather” and “Infeasible Sampling” provisions

Stormwater compliance questions like these are common—and getting them wrong can lead to violations, failed inspections, or lost No Exposure status. From determining permit applicability to managing inspections, sampling, and documentation, compliance quickly becomes complex, especially when state‑specific rules are layered on top of federal requirements.

That’s where J. J. Keller’s Water Permitting & Compliance Services can help. Our environmental consultants work directly with facilities to evaluate stormwater impacts, determine permitting and No Exposure eligibility, develop or refine SWPPPs, and help ensure inspections, corrective actions, and sampling requirements are met accurately and consistently. Whether you need help navigating day‑to‑day compliance or long‑term permit strategy, our experts provide practical guidance that reduces risk and simplifies compliance.