Stormwater/2026 NPDES Multi-Sector General Permit for Industrial Discharges: Airports Council International Comments on Proposed Federal Renewal

The Airports Council International – North America (“ACI”) submitted May 19th comments to the United State Environmental Protection Agency (“EPA”) regarding the proposed Multi-Sector General Permit (“MSGP”) for stormwater discharges associated with industrial activity. See Docket ID No. EPA-HQ-OW-2024-0481.

The MSGP is a general permit (as opposed to an individual permit) utilized by EPA to address stormwater discharges associated with thousands of different types of facilities in the United States.

The MSGP applies to any number of businesses in multiple industrial sectors. EPA’s MSGP is utilized in states that do not have primacy for this Clean Water Act program.

Note that Arkansas has been authorized to administer the National Pollutant Discharge Elimination System (“NPDES”) stormwater permitting program for many years. As a result, the EPA 2026 MSGP will not be applicable in the state of Arkansas. Nevertheless, states with primacy often take into account to some extent EPA’s choices (i.e., in terms of permit conditions and limitations) and revising or reissuing their general stormwater permits.

ACI notes by way of introduction that it represents local, regional, and state governing bodies that own and operate commercial airports in the United States and Canada. Its members are stated to operate over 300 airports in the United States which accounts for over 95% of the domestic passenger traffic and virtually all of the international airline passenger and cargo traffic in the United States. Over 400 aviation-related businesses are also stated to be members of ACI.

The trade association states that its interest in the MSGP is driven by the fact that most of its member airports are subject to NPDES regulations and require permits for discharge of stormwater from airport property. Concern is expressed that EPA has proposed what it characterizes as “significant expansions” of the MSGP that will impact airports and not provide any additional environmental benefits. It further states that state and local governments that operate United States airports cannot afford investing in regulatory compliance that is not “directly tied to, or focused on, specific environmental risk.”

Key concerns identified in the ACI comments include:

• PFAS Monitoring Requirements that are imposed on all airport operators (including questions and costs related to Method 1633 and 1621 testing and estimated costs per facility which are argued to be dramatically understated).
• Concern that MSGP requirements could constrain an airport’s flexibility in implementing the best stormwater management controls for their unique situation.
• Mandating coordination of activities between airports and their tenants, owners, and operators of regulated activities at the facilities (coordination requirements are argued to exceed EPA’s regulatory authority and encroach on regulatory authority of sister agencies such as FAA).
• Challenge of effectively implementing mandated coordination activities involving entities that are not governed by the MSGP.
• Specific sections of the MSGP for which ACI has concerns:
  • Section 8.S.22 Prohibition of Non-Stormwater Discharges (stating that not all stormwater flows occur during storm events).
  • Section 8.S.3.3 SWPPP Requirements (excessive regulatory burden on airport operator to coordinate development of the entire airport SWPPP).
  • Section 8.S.4.1.6 Source Reduction (inappropriate for EPA to establish source reduction expectations within a stormwater permit that may conflict with FAA requirements or establish stormwater permit compliance requirements that could impact the safety of airport and aircraft operations).
  • Section 8.S.4.1.7 Management of Stormwater (language does not reflect an in-depth understanding of deicing operations and practices at airports/nor does it address the varied size of airport and industrial activity subject to the permit).
  • Section 8.S.4.1.7 Management of Stormwater (language does not reflect the actual conditions encountered at airports with regard to deicing activity and the complexity of defining certain runoff as dry weather vs other runoff as wet weather).
  • Section 8.S.5.2 Potential Pollutant Sources (airport’s compliance with the MSGP cannot be dependent on activities over which the airport has no control).
  • Table 8.S-2 Ammonia Benchmark Monitoring (additional monitoring requirements for ammonia are not warranted).

A copy of the comments can be downloaded here.