Case Study: EPA Title V Air Quality Management System for a Fortune 100 Oil Refinery
What was breaking in the refinery's Title V permit application before this project?
An EPA Title V Clean Air Act permit for an oil refinery emissions upgrade is not a form submission. It is a documented proof of compliance built on tens of thousands of calculations covering emissions rates, standard deviations, and modeled scenarios that demonstrate the facility can meet the regulatory requirements it is applying to operate under. Every number in that proof has to be defensible, traceable to its source data, and reproducible on demand if a regulator questions it during application review.
The client was a Fortune 100 oil refinery preparing a Title V application for an emissions upgrade. The calculations required for the permit lived across spreadsheets, engineering documents, and disconnected files. Worst-case and best-case scenario modeling required for the case proofs depended on manual rebuilds of formulas every time inputs changed. The audit trail that EPA reviewers expect to see was not centralized. For a permit application of this scale and consequence, that infrastructure was not adequate to the regulatory burden.
For a Fortune 100 oil refinery, the consequences of a delayed or denied Title V application extend across the operation. Capital projects waiting on the permit cannot proceed. Production planning depends on the operational envelope the permit defines. Insurance, contracts, and downstream commitments all reference the regulatory standing of the facility. A Title V application built on infrastructure that cannot defend its own outputs is a risk multiplier across every business function the refinery touches.
What did PCG actually build for the Title V air quality environment?
PCG worked directly with refinery engineers, plant managers, compliance officers, and regulatory officials to map exactly what the permit application required and what the post-approval reporting cycle would demand. That direct engagement with the people who understood the regulatory framework was the only way to build a system where calculation outputs would hold up to EPA review and the audit trail would survive regulator inspection. Each component was built so that the integrity expected of a Fortune 100 permit submission was preserved at every layer.
The system integrated Microsoft Excel Solver as the real-time calculation engine for emissions rates, standard deviations, and scenario modeling. Solver handled the optimization-heavy computations the permit required while the surrounding application managed inputs, outputs, and version control. Calculations that had previously been built and rebuilt in standalone spreadsheets ran inside a controlled environment with traceable logic.
Every piece of source data that entered the system was stored in Microsoft Access with a complete chain of custody: when the data was entered, who entered it, where it came from, and how it had been used in subsequent calculations. The audit trail required for Title V review was captured automatically rather than reconstructed during the permit submission process.
EPA Title V applications require demonstrated case proofs across operational scenarios. The system included a scenario building tool that allowed compliance officers to construct, document, and store the worst-case and best-case emissions scenarios the application demanded. Each scenario was tied to its underlying calculations, so reviewers could trace any number in the application back to the inputs and logic that produced it.
The system included calculation integrity verification to confirm that the same input produced the same output across the application's lifecycle. For a regulatory document where reproducibility is a core review criterion, the verification layer was non-negotiable. EPA reviewers asking "show me how this number was produced" got a deterministic answer rather than an explanation that depended on remembering which spreadsheet version had been used.
The system was built to produce both the documentation formats required for the Title V application and the ongoing compliance reports DEP and EPA would require after the permit was issued. When the permit was approved, the same system that supported the application became the compliance tracking platform for the facility's continuing obligations. The application work and the operational compliance work shared one infrastructure.
A Title V permit application is not a documentation problem in the conventional sense. It is a calculation integrity problem. EPA reviewers do not primarily ask whether the operator has the right narrative around its emissions. They ask whether the numbers in the application are produced by a process that can be reproduced, audited, and defended. A spreadsheet-based application can technically contain the right numbers and still fail review because the path from source data to reported output is not traceable. The system PCG built closed that gap by making every number in the submission a query result rather than an artifact.
The decision to integrate Excel Solver as the calculation engine, rather than rebuilding the calculation logic from scratch in another platform, was deliberate. Solver had decades of validated use in emissions optimization work. Refinery engineers and compliance officers already understood it. Replacing it would have introduced a new validation burden for no compliance benefit. Wrapping Solver in a controlled application environment with proper data storage and audit trail produced a system that combined familiar calculation logic with the regulatory infrastructure the permit required.
What changed after the Title V system went into production?
The most consequential outcome was the permit approval itself. The Title V application produced by the system passed EPA review and the refinery received the Clean Air Act permit for its emissions upgrade. Beyond that single result, the system became the operating compliance platform for the facility's ongoing Title V obligations rather than being decommissioned at the end of the application cycle.
| Outcome | Result | How it was achieved |
|---|---|---|
| Title V Clean Air Act permit application | Approved | Application built on calculation integrity, scenario modeling, and audit trail at the standard EPA review requires |
| Calculation integrity across the application | Reproducible and auditable | Excel Solver integrated as controlled calculation engine with verification layer |
| Source data audit trail | Complete chain of custody | Microsoft Access database captured every input with user, timestamp, source, and downstream usage |
| Scenario modeling for case proofs | Documented and traceable | Scenario building tool stored worst-case and best-case scenarios linked to underlying calculations |
| Ongoing DEP and EPA reporting | Built into the same system | Post-approval compliance reporting produced as queries against the live application data |
| Time from input change to updated output | Real-time | Solver-driven recalculation eliminated manual formula rebuilds for scenario updates |
The strategic value of the system extended beyond the immediate permit approval. Once the calculation engine, audit trail, and reporting layer existed inside one controlled platform, the refinery's compliance posture against future regulatory changes improved structurally. Subsequent Title V renewals, modifications, and amendments could be supported by the same system rather than initiating new spreadsheet-based application cycles each time.
What capabilities does this kind of system provide for Clean Air Act compliance?
The infrastructure built for this Fortune 100 oil refinery addresses a problem class that appears across every regulated industrial operation under EPA Title V or comparable air quality permitting. The capabilities below apply to oil and gas refining, chemical manufacturing, power generation, cement and aggregate production, primary metals, and any operation where emissions calculations, scenario modeling, and audit-defensible reporting are part of the regulatory framework the operation runs under.
Tens of thousands of emissions calculations executed inside a controlled environment with traceable logic and reproducible outputs. Solver-based optimization wrapped in an application layer that preserves the audit trail EPA review requires.
Scenario building tool for the case proofs Title V applications require, with each scenario linked to underlying calculations. Reviewers asking how a specific projection was produced get a traceable answer rather than a reconstructed explanation.
Every input captured with user, timestamp, source, and downstream usage. The audit trail EPA expects during permit review and during post-approval inspections is preserved automatically rather than assembled retroactively from disconnected files.
The same system that supports the Title V application becomes the operational compliance tracking platform after permit approval. DEP and EPA reporting cycles run on the live data the application was built from rather than requiring separate reporting infrastructure.
Technology stack
| Component | Technology |
|---|---|
| Calculation engine | Microsoft Excel with Solver integration for emissions optimization |
| Database layer | Microsoft Access with Visual Basic for Applications (VBA) |
| Email and notifications | Exchange Server / Outlook integration |
| Audit trail | User, timestamp, source, and downstream usage captured per input |
| Scenario modeling | Worst-case and best-case scenario builder linked to underlying calculations |
| Calculation integrity | Verification layer for reproducibility across the application lifecycle |
| Regulatory framework | EPA Title V Clean Air Act with DEP reporting alignment |
Does this apply if your operation is smaller than a Fortune 100 oil refinery?
The architecture scales down as well as up. A regional industrial operator preparing a Title V application or operating under an existing Title V permit faces the same core problems as a Fortune 100 refinery: emissions calculations spread across spreadsheets, scenario modeling that requires manual rebuilds, audit trails that have to be reconstructed at the time of regulator inquiry, and reporting cycles that consume compliance staff time better spent on the actual operational work. The engineering decisions on this project, particularly the Excel Solver integration and the Access-based audit trail, transfer directly to operations of any industrial scale.
What makes this project transferable is not the size of the operation. It is the problem class. Any operation under EPA Title V, comparable state air quality permitting, or related Clean Air Act obligations is carrying the same calculation integrity risk this refinery was carrying before the system went live. The risk surfaces during permit applications, during renewals, during compliance audits, and during enforcement actions. A system that captures source data, runs calculations through a controlled engine, and preserves the audit trail automatically changes the operator's relationship with the regulator from defensive reconstruction to proactive readiness.
PCG has built EPA, DEP, and air quality compliance infrastructure for Fortune 100 and mid-market operators since 1995. The work documented here is one of more than 500 production applications PCG has delivered, with environmental and regulatory compliance representing approximately one-third of that volume across 31 years.
Frequently asked questions about EPA Title V air quality management systems
Allison has been building custom software since the early 1980s, including work as a data analyst for the U.S. Air Force before founding PCG in 1995. The Title V air quality management work documented here is one of more than 500 custom applications PCG has delivered, with environmental and regulatory compliance representing approximately one-third of that volume across 31 years. Her direct involvement in every project is not a policy. It is how PCG operates. When you call, she answers.
Project details documented with client permission. Specific identifying details about the Fortune 100 oil refinery have been generalized at client request. System capabilities and outcomes reflect the actual production deployment.
PCG founded 1995. Allison Woolbert's personal experience in software development predates PCG's founding.