St. Louis Petroleum Vapor Recovery Aligns with Kansas City: What EPA's April 23, 2026 Proposed SIP Approval Changes

If you run a gasoline dispensing facility, bulk plant, or terminal in the St. Louis metropolitan area, the April 23, 2026 Federal Register just handed you a rare thing in environmental compliance: a simplification.

EPA Region 7 has proposed to approve Missouri’s revisions to 10 CSR 10-5.220 — “Control of Emissions During Petroleum Liquid Storage, Loading and Transfer” — the rule that governs VOC emissions from petroleum liquid handling in the St. Louis ozone area (St. Louis City, Jefferson, St. Charles, Franklin, and St. Louis counties). The explicit purpose of the revision, per the Federal Register preamble, is to make the St. Louis rule “consistent with a similar rule that is applicable to the Kansas City area and regulates the same type of facilities.” The Kansas City analog is 10 CSR 10-2.260, which covers Clay, Jackson, and Platte counties.

Operators who run stations or terminals in both metros have been reading two similar but not identical rules for years. After EPA finalizes this approval, they will be reading one consistent standard.

The proposal was published April 23, 2026 at 91 FR 21751. Comments are due by May 26, 2026 through docket EPA-R07-OAR-2025-3822 on Regulations.gov. Here is what fuel operators, multi-site retailers, and petroleum distributors in the St. Louis metro need to know before the window closes.

What the 2026 SIP Revision Actually Changes

Four changes drive the update. None of them rewrite the bones of the rule — Stage I controls at unloading are still in, P/V valves are still required, and the testing cycles at the tank are still on the same schedule. What changes is the administrative surface and the small-tank applicability:

1. Small-tank applicability threshold moves from 500 gallons to 550 gallons. Any gasoline storage tank greater than 550 gallons (and less than 40,000 gallons) in the St. Louis area is subject to the rule. The previous version kicked in at 500 gallons. Tanks in the narrow 500-to-550-gallon window that were formerly in scope come out of scope. This aligns with the Kansas City rule, which already used the 550-gallon threshold.

2. The construction permit requirement for vapor recovery system modifications at gasoline dispensing facilities goes away. Under the prior rule, a GDF modifying its VR system had to pull a construction permit under 10 CSR 10-6.060. Under the revised rule, a streamlined procedural process inside 10 CSR 10-5.220 itself replaces that permitting step. This is a real operational win — the construction-permit route involved filing fees, processing fees, and MDNR review time that no longer apply to straightforward VR system modifications.

3. Testing and reporting language is clarified. The revisions tighten definitions, remove duplicative language, and update the incorporations by reference to other Missouri rules. The underlying testing cycles are unchanged — tanks greater than 2,000 gallons still pass a pressure decay test and a pressure/vacuum valve test at installation, then a pressure decay test every 6 years and a P/V valve test every 3 years.

4. Definitions and structure align with 10 CSR 10-2.260. Definitions specific to the rule are added and administrative structure is harmonized with the Kansas City analog. For a multi-site operator, that means one vocabulary and one rule structure to train a compliance team against, not two.

The Applicability Map You Should Re-Confirm

Before the comment period closes, every St. Louis-area fuel operator should run a quick applicability recheck on any tank that sits near the threshold. The specific question: are there any tanks between 500 and 550 gallons on site that were previously subject to 10 CSR 10-5.220?

Yes, and the tank is between 500 and 550 gallons → the tank moves out of scope once the revised rule is federally approved. Document the applicability determination and note the effective date of the change.
Yes, the tank is greater than 550 gallons → the tank remains subject. Continue existing P/V valve, vapor recovery, and testing obligations.
No tanks near the threshold → no action required on applicability, but the streamlined VR-modification process is now available to you.

For any tank greater than 2,000 gallons, the core technical requirements continue per MDNR’s current guidance:

California Air Resources Board (CARB)-certified or MDNR-approved pressure/vacuum valves on all tank vents
Positive pressure setting: 2.5 to 6.0 inches of water column
Negative pressure setting: 6.0 to 10.0 inches of water column
Vapor recovery system demonstrating 90% collection efficiency
Pressure decay test at installation, then every 6 years
P/V valve test at installation, then every 3 years

None of those requirements are changing in 2026. What is changing is how you modify the VR system and the threshold for smaller tanks.

Stage II Is Still Gone — and That’s Not What the 2026 Revision Is About

For clarity, because this still comes up on compliance calls: the 2026 revision has nothing to do with Stage II vapor recovery. Stage II equipment — the coaxial nozzles that captured gasoline vapors at the pump — was decommissioned at St. Louis-area GDFs by December 31, 2015, under a 2015 update to 10 CSR 10-5.220. That decommissioning followed EPA’s May 16, 2012 finding that Onboard Refueling Vapor Recovery (ORVR) systems on vehicles had reached widespread use, which authorized states with Stage II programs to remove them from their SIPs.

What remains in place — and always has — is Stage I balance loading. That’s the capture system that pulls vapors back into the delivery truck during fuel unloading at the underground storage tank. Stage I is unchanged in 2026. If your Stage I system is out of compliance or was never fully installed, the 2026 SIP revision does not relieve you of that obligation.

What Multi-Site Operators Gain

The biggest operational payoff for the 2026 alignment lands on fuel operators running stations across both metros. Before the revision:

St. Louis sites followed 10 CSR 10-5.220, with a 500-gallon small-tank threshold and a construction-permit requirement for VR modifications.
Kansas City sites followed 10 CSR 10-2.260, with a 550-gallon threshold and different administrative mechanics.

After the revision is finalized:

Both sites read a single applicability threshold (>550 gallons).
Both sites use a streamlined procedural process for VR system modifications — no construction permit required for routine VR changes at a GDF.
The definitions and rule structure match, so compliance training, internal SOPs, and vendor specifications written for one metro carry over cleanly to the other.

For a regional operator with stations in Ballwin, Creve Coeur, and Chesterfield alongside stations in Lee’s Summit, Independence, and North Kansas City, this is one less administrative seam.

What This Does Not Change

To be specific about boundaries: the 2026 SIP revision does not change the following.

Stage I balance controls at unloading are still required at subject GDFs and bulk plants.
P/V valve pressure settings remain 2.5–6.0 in. water column positive and 6.0–10.0 in. water column negative for subject tanks.
Vapor recovery systems on tanks >2,000 gallons still require 90% collection efficiency.
Testing cycles are the same — pressure decay every 6 years, P/V valve every 3 years.
The upper applicability ceiling stays at <40,000 gallons.
Petroleum facilities outside the St. Louis and Kansas City ozone areas are unaffected. 10 CSR 10-5.220 and 10 CSR 10-2.260 apply only in their respective metro areas.
Federal NESHAP 40 CFR 63 Subpart CCCCCC (area-source standards for GDFs) continues to apply everywhere GDFs meet its threshold. Missouri’s rules are in addition to, not instead of, the federal NESHAP.

The Illinois Side of the St. Louis Metro Is a Different Story

One frequent source of confusion: operators running stations on the Illinois side of the St. Louis metro — Madison, St. Clair, Monroe counties — do not fall under 10 CSR 10-5.220. Illinois runs its own SIP and its own gasoline dispensing rules through Illinois EPA. The 2026 Missouri alignment does not extend across the state line. If you operate a station on both sides of the Mississippi, you still read two state rules; the 2026 revision only harmonizes the Missouri side.

Similarly, Kansas-side Kansas City operators (Wyandotte, Johnson counties) fall under K.A.R. 28-19 through KDHE. The Missouri 2026 action does not change Kansas requirements.

Comment by May 26, 2026 — If It Matters to Your Operation

EPA’s comment period on docket EPA-R07-OAR-2025-3822 runs through May 26, 2026. Comments go through Regulations.gov. Operators with specific technical or implementation concerns — the mechanics of the new streamlined VR-modification process, the documentation requirements for applicability redeterminations at the 550-gallon threshold, interactions with the federal GDF NESHAP — have a short window to put those concerns on the record.

If your fleet of sites includes tanks that will move in or out of scope at the new threshold, if your planned VR system modifications would benefit from clarity on the streamlined procedural process, or if your compliance team uses cross-metro standardized SOPs and wants EPA to make the alignment explicit in the final approval language, this is the comment period to use.

Practical Next Steps for St. Louis-Area Fuel Operators

Before the final approval takes effect, walk through five specific actions:

Re-confirm applicability at the 550-gallon threshold. Document in writing any tank that moves in or out of scope.
Update internal SOPs to reference the streamlined procedural process for VR system modifications, not the 10 CSR 10-6.060 construction permit path.
Pull the current status of all P/V valve tests and pressure decay tests for subject tanks. The 3-year and 6-year cycles quietly lapse on busy sites.
Check Stage II decommissioning completeness. Any site with residual Stage II equipment installed — even if nonfunctional — should document decommissioning per the 2015 deadline.
If you operate in both St. Louis and Kansas City metros, converge your two compliance programs into one standardized program now. The 2026 alignment is the opening to do that cleanly.

When iSi Steps In

iSi supports petroleum facility operators in both the St. Louis and Kansas City metros with vapor recovery applicability determinations, P/V valve and pressure decay testing coordination, compliance program documentation, and comment support for SIP revisions that materially affect your operation. If your sites straddle the 550-gallon threshold or you are planning a VR system modification that would have previously required a construction permit, the next step is a 30-minute applicability and compliance-path review.