Planning a refinery turnaround in the Dallas area means working inside one of the most closely watched VOC control jurisdictions in Texas. The rules here involve two separate agencies with two different destruction efficiency thresholds, and the documentation requirements are specific enough that a compliance plan built to the wrong standard will not hold up under inspection. Getting the vapor control requirements confirmed before your outage scope is locked is how you avoid permit deviations, scheduling delays, and compliance gaps that surface during an agency audit months after the job is done.
We have handled refinery turnaround vapor control since 1992, working planned outages across the Texas Gulf Coast for operators including ExxonMobil, Shell, Valero, Chevron, and Phillips 66. Below is a clear breakdown of what Dallas area petroleum refineries are actually required to do under state and federal rules, where those rules create real engineering decisions for your team, and what to look for when selecting a vapor control contractor for a planned outage.
What Makes Dallas Different From the Rest of Texas
The Dallas area carries two active ozone nonattainment classifications that cover a 10-county region, and both impose VOC control obligations on every petroleum refinery inside that boundary. Under the 2008 eight-hour ozone standard (0.075 ppm), the area covering Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, Tarrant, and Wise Counties is classified as severe nonattainment, with an attainment deadline of July 20, 2027. Under the 2015 eight-hour ozone standard (0.070 ppm), a nine-county area covering the same counties minus Rockwall carries a serious nonattainment classification, with an attainment deadline of August 3, 2027. Both designations are confirmed on the TCEQ Dallas-Fort Worth attainment status , which is the authoritative reference for verifying which standard applies to your facility’s specific county.
Both classifications impose VOC control requirements on petroleum refineries operating within the nonattainment boundary, and the more demanding standard in any given situation is the one that governs your facility’s obligations. The severe classification under the 2008 standard carries particular weight because severe nonattainment areas face tighter control obligations under the Clean Air Act, and because TCEQ adopted a Section 185 Failure to Attain Fee program for this nonattainment area in October 2025 that applies to major stationary VOC sources if the region misses its 2027 deadline. That makes turnaround vapor control planning a budget issue for Dallas area refineries, not only a permit compliance one.
What TCEQ Requires Step by Step During a Dallas Refinery Turnaround
The governing state rule for refinery turnarounds in the Dallas area is 30 TAC Chapter 115, Subchapter D, Division 1. It covers process unit shutdown and turnaround operations, vacuum-producing systems at petroleum refineries, and includes specific testing, monitoring, and recordkeeping requirements. The control sequence under §115.312 has three required steps that must be completed in order.
Drain all pumpable and drainable liquid first: Before any venting begins, you must recover and store all liquid that can be removed from the unit. This is the first required action in the control procedure, not a recommended practice, and shortcutting it to protect schedule creates a compliance gap in your records before your vapor control equipment is even connected to the vessel.
Reduce vessel pressure to 5 psig or below before venting to atmosphere: Vessel gas pressure must be brought to 5 psig (34.5 kPa gauge) or below by recovery or combustion before any venting to the atmosphere takes place. You cannot depressure a unit by simply opening it to air, and the method used to reduce pressure must generate a record your EHS team can produce for a TCEQ inspector.
Control all covered vent gas streams to at least 90% VOC efficiency: Vent gas streams must be controlled with a minimum efficiency of at least 90%, or reduced to a VOC concentration of no more than 20 parts per million by volume on a dry basis corrected to 3.0% oxygen for combustion devices. Acceptable control methods under §115.312 include a direct-flame incinerator operating at or above 1,300 degrees Fahrenheit, a smokeless flare, or any other approved vapor control system as defined under §115.10.
The same 90% threshold applies to vacuum-producing systems at petroleum refineries in the Dallas area, including mechanical vacuum pumps and steam ejectors used during turnaround operations. If your outage involves vacuum-producing equipment, those streams fall under the same division and must be controlled to the same standard. Compliance records under §115.316 must be continuous throughout the turnaround, covering temperature monitoring downstream of incinerators, upstream and downstream monitoring for catalytic systems, and continuous exhaust gas VOC concentration monitoring for any carbon adsorption system, none of which can be reconstructed as an end-of-job summary after the outage window closes.
How the EPA Refinery Sector Rule Raises the Bar Above the TCEQ Standard
Meeting TCEQ’s 90% threshold is a state law requirement, but for most Dallas area refineries it is not the number that creates the greatest compliance exposure during a planned outage. The EPA’s Refinery Sector Rule under 40 CFR §63.670 applies a separate and more demanding set of standards to Maintenance, Startup, and Shutdown events at covered petroleum refineries, and both sets of rules apply simultaneously with TCEQ’s Chapter 115 requirements.
Under §63.670(o), refineries must develop and implement a written Flare Management Plan that includes procedures to minimize or eliminate discharges to the flare during planned startup and shutdown of process units and ancillary equipment connected to affected flares. That plan must be current, on file, and followed exactly before any MSS event involving streams connected to an affected flare. The EPA RSR prohibits routine flaring during MSS activities and requires at least 98% destruction efficiency on all depressuring vents, with uncontrolled releases triggering fines exceeding $100,000 per day and federal operating permit violations.
That gap between 90% and 98% is where most turnaround vapor control plans fall short in practice. A smokeless flare satisfies the TCEQ threshold under §115.312 but does not reliably reach 98% destruction efficiency across variable vapor compositions during a multi-unit depressuring event. Your plan must be built to the federal standard because that is the one with the higher financial exposure and the harder documentation requirements, and for most Dallas area refineries subject to both rules, mobile thermal oxidizers are the only equipment type that consistently satisfies both agencies from a single deployment.
Why Your Existing Flare System Will Not Cover a Multi-Unit Dallas Turnaround
A smokeless flare qualifies as an acceptable control method under §115.312 for TCEQ purposes, but most Dallas area refinery teams find that relying on their existing flare system for a planned multi-unit outage creates three separate problems before the end of the first week.
The first problem is header capacity, which catches many turnaround teams off guard when the combined vapor load from simultaneous depressuring and steam-out operations exceeds what the flare gas recovery system can handle, forcing a choice between delaying the critical path or creating a compliance event.
The second problem is the RSR Flare Management Plan requirement, which obligates your facility to assess whether discharges to the flare can be minimized or prevented and to describe minimization alternatives that have been or will be implemented, making it difficult to justify defaulting to the existing flare when mobile thermal oxidizers are technically available and staged nearby.
The third problem is destruction efficiency consistency across shifting vapor compositions, because under the RSR flares must demonstrate either 96.5% combustion efficiency or 98% destruction efficiency and must maintain a minimum combustion zone net heating value of 270 BTU per standard cubic foot based on 15-minute time block averages, which requires monitoring and fuel gas management that standard flare operation is not designed to provide across the variable streams a multi-unit turnaround produces. Mobile thermal oxidizers sized specifically for your turnaround solve all three problems by operating independently of the existing flare, handling the vapor loads your specific outage produces, and generating the continuous destruction efficiency records both agencies require. Our Port Arthur flareless hydrocracker turnaround is a direct example of this approach, where we ran simultaneous thermal oxidation across multiple process units with zero flaring and full TCEQ and EPA RSR compliance throughout the project.
What H2S in the Vapor Stream Means for Your Dallas Turnaround Engineering Plan
Many refineries in and around the Dallas area process sour crude, and when a unit that has been in sour service comes down for turnaround the vapor stream contains hydrogen sulfide at concentrations that may be far higher than pre-job sampling suggested. H2S creates two distinct problems that must be resolved upstream of your thermal oxidizer before depressuring begins.
The first problem is personnel safety, because H2S at concentrations above 10 parts per million causes symptoms within minutes and depressuring streams from sour process units can carry H2S at tens of thousands of parts per million, putting workers near the vapor control tie-in points in the hazard zone if sour inlet streams reach an oxidizer without upstream scrubbing.
The second problem is permit compliance, because high-concentration H2S combustion produces sulfur dioxide in quantities that can exceed your facility’s air permit thresholds if the sour stream goes directly to an oxidizer without upstream treatment. The correct engineering sequence is liquid scrubber treatment first to neutralize the H2S, followed by thermal oxidation for final VOC destruction, and our vapor scrubbing and H2S control service covers the full range of ESCRUB and VapoScrub configurations we deploy upstream of thermal oxidizers on sour stream projects. In our Gulf Coast flareless multi-unit turnaround, specialty liquid scrubbers neutralized inlet H2S concentrations up to 100,000 ppm before routing vapor streams to EMTOS and EMECS thermal oxidizers, which delivered greater than 99.99% destruction removal efficiency across all vapor compositions, with zero flaring, zero fines, and the turnaround completed ahead of schedule.
Your turnaround vapor control plan needs to account for the worst-case H2S concentration in each stream being controlled, based on sampling from the actual unit, before any equipment is sized. A contractor who estimates equipment without confirmed H2S data from your specific streams is planning for conditions that may not match your facility.
What Your EHS Team Needs From a Contractor’s Documentation System
TCEQ and EPA compliance records for a Dallas area refinery turnaround must be continuous, specific, and available without delay. A project summary assembled after the job ends does not satisfy the monitoring requirements under §115.316, and it does not satisfy the root cause analysis and deviation documentation requirements under the EPA RSR if something changes during the outage.
Every client gets access to their project data through our ENFORCE digital compliance portal, which captures PID and FID calibration records, continuous destruction efficiency readings, degassing logs, and field observations in real time throughout the project. All records are posted within 72 hours of job completion and remain accessible for seven years, covering the standard TCEQ retention window, so your EHS team can pull current project data while the job is still running without waiting for us to send a file. When a TCEQ inspector arrives or an EPA audit is triggered, your compliance package is already complete, organized, and timestamped because it was captured continuously throughout the job.
What to Look for When Selecting a Vapor Control Contractor for a Dallas Turnaround
The requirements covered above explain why not every vapor control contractor is equipped for a Dallas area petroleum refinery planned outage, and below are the factors that matter most when evaluating vendors for this specific work.
Thermal oxidizer fleet capacity and staging location: Thermal oxidizers are what get you to the 98% RSR destruction standard across variable vapor loads, so ask how many units the contractor can deploy to your site simultaneously, what their maximum rated inlet flow covers, and where the nearest equipment is staged relative to Dallas.
H2S scrubbing capability for sour service units: If any of your turnaround units have been in sour crude service, the contractor needs liquid scrubber capacity sized for the worst-case H2S concentration in each controlled stream, not a general statement that they handle sour service.
References from Texas refineries matter more than general claims: Ask for EHS managers or turnaround managers at comparable-scale Texas or Gulf Coast petroleum refineries who can speak to how the contractor performed when conditions changed mid-outage, not just on a straightforward job.
“I would like to thank these guys for their hard work, which was done on a high-risk degassing tank and was executed flawlessly on their part.”
Tank Maintenance Process Planner at Exxon
Real-time compliance documentation: Ask specifically how continuous monitoring data is captured during the job, how quickly it is available to your team, and whether it is formatted for TCEQ and EPA reporting, because an end-of-job summary is not sufficient for a Dallas turnaround and a contractor who cannot show you a live compliance portal before the job starts will struggle to produce defensible records under inspection.
A verifiable zero-incident safety record: The standard to hold any contractor to is a 0.0 Total Recordable Incident Rate, so ask for the number and the documentation behind it rather than a general description of safety culture, because our 0.0 TRIR across thousands of site hours reflects the site-specific safety plans and OQ-qualified crews we put in place before work starts on every project.
Frequently Asked Questions
Does TCEQ’s 90% VOC control requirement under 30 TAC Chapter 115 apply to all petroleum refineries in the Dallas area regardless of facility size?
Yes. The requirement applies to all petroleum refineries under 30 TAC Chapter 115, Subchapter D across the Dallas area nonattainment region, which under the 2008 ozone standard covers Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, Tarrant, and Wise Counties, and facility throughput or unit count do not change that applicability. Confirm the specific applicability of individual units with your environmental counsel or reach out directly to the TCEQ Air Quality division with questions about your facility.
Why does the EPA Refinery Sector Rule require 98% destruction efficiency when TCEQ only requires 90%, and do both apply at the same time?
Yes, both rules apply simultaneously and carry separate documentation obligations, with TCEQ’s 30 TAC Chapter 115 requiring 90% VOC control as part of the Texas State Implementation Plan and the EPA RSR under 40 CFR §63.670 requiring 98% minimum destruction efficiency on depressuring vents as a federal MACT standard governing MSS events. A turnaround plan built only to the TCEQ threshold falls short of the federal standard and carries the penalty exposure described above, which is why we build every thermal oxidizer deployment to the 98% RSR standard so your compliance package satisfies both agencies from the same equipment.
Can our refinery rely on its existing flare system to meet vapor control requirements during a planned Dallas turnaround?
Yes, a smokeless flare technically qualifies under §115.312 for TCEQ purposes, but for most Dallas area refineries with multiple units coming down together, the existing flare system creates header capacity constraints, RSR Flare Management Plan obligations around minimization assessment, and destruction efficiency consistency challenges that mobile thermal oxidizers deployed specifically for the turnaround avoid entirely while producing the continuous records both agencies require.
Do we need additional equipment beyond a thermal oxidizer if our turnaround streams contain H2S?
Yes, high-concentration H2S requires upstream liquid scrubber treatment before any vapor stream reaches a thermal oxidizer, because combusting sour streams without first removing the H2S produces sulfur dioxide at levels that can exceed air permit thresholds. Your vapor control plan needs confirmed H2S sampling data from each controlled stream before equipment is sized, not a general estimate based on crude type or historical process data.
What compliance documentation does TCEQ require during a refinery turnaround in the Dallas area, and how does your team produce it?
Yes, TCEQ requires continuous records throughout the turnaround under §115.316, covering temperature monitoring downstream of direct-flame incinerators, upstream and downstream monitoring for catalytic systems, and continuous exhaust gas VOC concentration monitoring for carbon adsorption systems. On top of those state requirements, the EPA RSR requires Flare Management Plan compliance records, destruction efficiency verification through approved stack testing, and root cause analysis for any deviation event, all of which we capture in real time through the ENFORCE client compliance portal and post within 72 hours of job completion.
Should a Dallas area refinery engage a vapor control contractor before the turnaround scope is finalised?
Yes, and the earlier the engagement the better, particularly for multi-unit outages where simultaneous vapor loads require a phased equipment deployment plan, because reviewing P&IDs, confirming vapor flow rates and H2S concentrations, developing a site-specific safety plan, and pre-positioning assets near your facility all take time that cannot be recovered once the outage window opens. We operate 24/7 for urgent situations when schedules shift without notice.
Does your team have direct experience with refinery turnaround vapor control in Texas?
Yes, we have served Texas petroleum refineries since 1992 working planned outages for operators including ExxonMobil, Shell, Valero, Chevron, and Phillips 66, and you can see our approach to a Texas turnaround involving thermal oxidation, H2S scrubbing, and water treatment in our Houston area FCCU turnaround case study, where the job completed on schedule with full TCEQ and EPA RSR compliance and zero incidents.
How do we get started for a planned Dallas area outage?
Call our team directly at 888-997-9465, available 24 hours a day, or submit your unit types, expected vapor stream composition, and turnaround timeline through our project inquiry form and we will come back with a project approach covering equipment selection, H2S treatment requirements, site safety planning, vapor flow phasing, and compliance documentation from start to finish.
Contact Our Team Before Your Next Dallas Refinery Turnaround
If your facility has a planned outage coming up and you want to confirm the right vapor control approach for your specific units and stream compositions, our team can review your requirements and work through the details with you. We have handled this work since 1992 and carry the fleet, the documentation systems, and the safety record to back it up on every project. Call us at 888-997-9465, available 24 hours a day, or request a quote and our team will come back with a project approach built around your facility’s specific compliance requirements.
