Rule 1147 Compliance in California: NOx Testing, CO Testing & Source Testing Requirements
Is your combustion equipment ready for South Coast AQMD Rule 1147 compliance?
If your facility operates permitted gas- or liquid-fueled combustion equipment that is not covered by another Regulation XI rule, South Coast AQMD Rule 1147 – NOx Reductions from Miscellaneous Sources may apply to your equipment. The rule is designed to reduce NOx emissions while limiting CO emissions.
For manufacturers, industrial facilities, commercial operations, environmental managers and plant owners, understanding Rule 1147 is important because compliance can involve emission limits, source testing, monitoring, combustion-system maintenance, recordkeeping and permit requirements.
Important: Rule 1147 is a South Coast AQMD rule, not a uniform statewide California requirement.
What Is Rule 1147?
Rule 1147 – NOx Reductions from Miscellaneous Sources applies to manufacturers, distributors, retailers, installers, owners and operators of gaseous- and/or liquid-fueled combustion equipment that requires a South Coast AQMD permit when another Regulation XI rule does not apply.
The current adopted rule was amended May 6, 2022.
Rule 1147 can cover a wide range of equipment, including:
Ovens
Dryers
Heaters
Furnaces
Kilns
Calciners
Cookers
Roasters
Heated tanks
Thermal oxidizers
Catalytic oxidizers
Afterburners
Vapor incinerators
Evaporators
Fryers
Parts washers
Autoclaves
Make-up air heaters
Certain turbines
Other miscellaneous combustion equipment
The exact applicability depends on the equipment, permit status, fuel, heat-input rating and whether another South Coast AQMD rule applies.
Why Rule 1147 Matters to California Industries
NOx emissions contribute to ozone and other air-quality problems. Rule 1147 establishes emission requirements intended to reduce NOx from combustion sources while also establishing CO limits for applicable equipment.
For businesses, compliance is not simply about having a permitted burner.
You need to demonstrate that applicable equipment continues to meet the required emission limits under the applicable compliance pathway.
2026 Rule 1147 Update: What Businesses Need to Know
The major regulatory change remains the May 6, 2022 amendment, which introduced updated NOx and CO limits, implementation schedules, monitoring/source-testing requirements, revised exemptions and provisions affecting both RECLAIM and non-RECLAIM facilities.
South Coast AQMD’s current official rule book lists Rule 1147 as amended May 6, 2022.
South Coast AQMD also provides a Rule 1147 Guidance Document dated March 7, 2025, which explains applicability, implementation schedules and source-testing requirements.
What does this mean in 2026?
Facilities should not rely on an old compliance checklist.
Your team should verify:
Current Rule + Current Permit + Equipment Age + Rated Heat Input + Previous Test Date + Applicable Compliance Schedule
Which Equipment Can Be Affected?
Rule 1147 has a broad equipment scope.
Examples include:
🔥 Industrial Heating Equipment
Furnaces
Heaters
Ovens
Dryers
Kilns
Calciners
Roasters
🏭 Process Equipment
Heated process tanks
Evaporators
Parts washers
Autoclaves
Cookers
🌡️ Air & Pollution-Control Equipment
Make-up air heaters
Thermal oxidizers
Catalytic oxidizers
Afterburners
Vapor incinerators
⚡ Other Combustion Equipment
Certain turbines and miscellaneous gas- or liquid-fired units may also fall within the rule.
Equipment Below 325,000 BTU/hr
One important exemption is that Rule 1147 does not apply to units with a heat-input rating below 325,000 Btu/hr, subject to the rule’s other provisions. Charbroilers and food ovens are also specifically excluded.
This is one reason a facility should perform an equipment-by-equipment applicability review rather than assuming every combustion device is regulated identically.
Rule 1147 NOx & CO Limits
The rule uses different emission limits depending on:
Equipment category
Fuel type
Process temperature
Equipment age/status
Applicable compliance schedule
For example, Table 2 includes requirements such as:
These are reference examples from Table 2, not a substitute for determining the limit applicable to a particular unit.
The “Less Than 1 Pound of NOx Per Day” Option
One of the important Rule 1147 compliance pathways allows an owner/operator to elect to demonstrate that NOx emissions are less than one pound per day averaged over a calendar month, subject to the rule’s requirements.
This can involve a non-resettable totalizing time meter or fuel meter and prescribed operating/fuel-use limits.
For example, the rule provides monthly operating-hour limits based on rated heat input for certain units:
Below 1 MMBtu/hr: 240 hours/month
1 to below 1.5 MMBtu/hr: 160 hours/month
1.5 to 2 MMBtu/hr: 120 hours/month
The actual compliance pathway must be evaluated against the rule and facility conditions.
Rule 1147 Source Testing Requirements
This is where professional emissions testing becomes particularly important.
Rule 1147 requires applicable compliance determinations to use a South Coast AQMD-approved source-test protocol and test under specified operating conditions. Testing generally uses a period of at least 15 minutes and no more than 60 consecutive minutes, unless an alternative period is approved.
Testing must be performed after startup and at the unit’s normal firing rate.
For specified equipment categories, an additional compliance determination may be required at low heat input or during a specified period after startup.
Source-Test Protocol: A Critical Step
Don’t wait until the testing date to think about the protocol.
Rule 1147 requires the source-test protocol to be submitted to the Executive Officer for approval no later than 90 days before the scheduled source test.
Typical process:
Rule Review
↓
Equipment Review
↓
Test Protocol Development
↓
Protocol Submission
↓
Regulatory Approval
↓
Field Testing
↓
Data Analysis
↓
Compliance Report
This is one reason early scheduling is important.
Required Testing Frequency
For applicable units with NOx emissions ≥1 pound/day, Rule 1147 establishes source-testing frequencies based on rated heat input capacity:
Units <10 MMBtu/hr
Every 5 calendar years
Units ≥10 and <40 MMBtu/hr
Every 3 calendar years
Units ≥40 MMBtu/hr
Every calendar year
The rule also establishes minimum intervals between tests and special provisions for units that have been shut down for extended periods.
This makes one thing clear:
Knowing your last test date is not enough.
You need to know the rated heat input and applicable compliance category.
Who Can Conduct Rule 1147 Testing?
Rule 1147 requires applicable compliance determinations to be performed using an independent contractor approved by the Executive Officer under the Laboratory Approval Program for the applicable test methods.
This is an important consideration when selecting a testing company.
Before scheduling your test, verify:
Appropriate test-method approval
Qualified personnel
Proper instrumentation
Calibration procedures
QA/QC
South Coast AQMD experience
Reporting capability
What Is Tested?
Depending on the equipment and compliance pathway, testing can involve:
NOx
The primary pollutant targeted by Rule 1147.
CO
Rule 1147 also establishes CO requirements for applicable equipment.
Oxygen
O₂ measurements are used in applicable emission calculations and correction procedures.
Carbon Dioxide
CO₂ may also be measured as part of applicable source-test procedures.
South Coast AQMD Method 100.1 and Method 10.1 are among the methods identified in Rule 1147 for applicable compliance determinations.
Rule 1147 Maintenance Requirements
Testing alone is not enough.
Rule 1147 requires owners/operators to perform combustion-system maintenance according to the manufacturer’s schedule and specifications and maintain the relevant records.
Rule 1134 Compliance in California: Stationary Gas Turbine NOx Testing, Monitoring & Source Testing Guide
Does your facility operate a stationary gas turbine in Southern California?
If yes, South Coast AQMD Rule 1134 – Emissions of Oxides of Nitrogen from Stationary Gas Turbines may be an important part of your air-quality compliance program.
Rule 1134 establishes NOx emission requirements and monitoring/source-testing provisions for applicable stationary gas turbines. The rule is particularly important for facilities operating larger turbines, turbines with catalytic controls, and turbines located at non-RECLAIM NOx facilities.
South Coast AQMD currently lists Rule 1134 as amended February 4, 2022. It also currently lists a Proposed Amended Rule 1134 in its active rulemaking section, meaning facilities should continue monitoring regulatory developments in 2026.
For facility owners, plant managers and EHS professionals, the message is simple:
Don’t wait for a compliance test to reveal an emissions problem.
Rule 1134 California
What Is Rule 1134?
Rule 1134 – Emissions of Oxides of Nitrogen from Stationary Gas Turbines is a South Coast AQMD source-specific rule intended to control NOx emissions from stationary gas turbines.
It is part of South Coast AQMD’s Regulation XI, which contains source-specific standards. The current rule book identifies Rule 1134 as applying to emissions of oxides of nitrogen from stationary gas turbines and shows its latest adopted amendment as February 4, 2022.
Important:
Rule 1134 is not a statewide California rule.
It applies within the South Coast AQMD jurisdiction when the facility/equipment meets the rule’s applicability provisions.
Facilities elsewhere in California may be subject to requirements established by their local air district.
Why Does Rule 1134 Matter?
NOx is a major air pollutant associated with combustion equipment.
NOx can contribute to:
Ozone formation
Smog
Nitrogen dioxide pollution
Fine particulate formation
Regional air-quality problems
South Coast AQMD developed Rule 1134 specifically to reduce NOx emissions from stationary gas turbines.
For businesses, however, compliance is not simply about operating a turbine.
It is about being able to demonstrate that the turbine is operating within the applicable regulatory and permit requirements.
Which Gas Turbines Can Be Subject to Rule 1134?
The rule contains specific applicability provisions and exemptions.
Historically and under the current rule framework, stationary gas turbines rated at 0.3 MW or greater are an important category.
South Coast AQMD’s compliance guidance states that, beginning January 1, 2024, owners/operators of stationary gas turbines rated 0.3 MW or larger must operate within the applicable Table I NOx emission limits, subject to the rule’s provisions.
Potentially affected equipment can include:
Industrial gas turbines
Cogeneration turbines
Combined-cycle turbines
Power-generation turbines
Turbines at wastewater facilities
Natural-gas-fired turbines
Turbines with SCR systems
Turbines at non-RECLAIM NOx facilities
But don’t assume every turbine has identical requirements.
Applicability depends on factors including:
Turbine size + installation history + facility status + fuel + control technology + operating conditions + permit conditions
2026 Update: What Facilities Should Know About Rule 1134
There are two important points for businesses in 2026.
1. The Current Adopted Rule
South Coast AQMD’s official rule book identifies Rule 1134 as amended February 4, 2022.
The 2022 amendment included changes involving:
NOx requirements
Recuperative gas turbines
Selective catalytic reduction (SCR)
CEMS provisions
Monitoring requirements
Startup/shutdown provisions
Liquid-fuel use during natural-gas curtailments at certain health facilities
South Coast AQMD’s February 2022 Governing Board materials describe these amendments and their purpose.
2. Rule 1134 Is Also Listed in Active Rulemaking
South Coast AQMD’s current Active Proposed Rules page lists Proposed Amended Rule 1134 among rules currently in the proposal/amendment process.
The dedicated Rule 1134 proposal page contains the 2021 amendment-development materials, including draft rule language, staff reports and public-hearing documents.
What does this mean for industry?
A proposed amendment is not automatically an adopted requirement.
Facilities should comply with the currently adopted rule and permit conditions while monitoring the rulemaking process for future changes.
Rule 1134 NOx Emission Limits
Rule 1134 contains NOx limits based on turbine size and applicable technology.
The rule’s reference limits include categories such as:
Stationary Gas Turbine
Reference NOx Limit
0.3 to <2.9 MW
25 ppm
2.9 to <10 MW
9 ppm
2.9 to <10 MW, No SCR
15 ppm
10 MW and larger
9 ppm
10 MW and larger, No SCR
12 ppm
≥60 MW Combined Cycle, No SCR
15 ppm
≥60 MW Combined Cycle
9 ppm
There are additional provisions and special categories, including turbines using qualifying sewage-digester-gas fuel. The applicable compliance calculation can also involve the turbine’s demonstrated or manufacturer-rated efficiency.
Important:
Never determine your compliance obligation from a generic table alone.
The applicable limit can depend on the specific turbine, control technology, permit and rule provisions.
Why NOx Testing Is Important
A gas turbine can appear to operate normally while its NOx emissions change because of:
Combustion conditions
Fuel characteristics
Turbine load
Air/fuel ratio
Burner condition
SCR performance
Catalyst condition
Ammonia injection
Control-system performance
Maintenance condition
Therefore:
Normal operation does not automatically mean compliant emissions.
Professional emissions testing provides objective data.
Rule 1134 Source Testing
For applicable turbines that do not use a CEMS, Rule 1134 includes source-testing requirements.
The rule provides for measurement of parameters including:
NOx concentration
Carbon monoxide concentration
Turbine efficiency, where applicable
NOx and CO concentrations are expressed in ppm by volume and corrected to 15% oxygen on a dry basis, according to the rule’s provisions.
This is where professional source testing becomes critical.
A compliant test requires more than simply taking an emissions reading.
It requires:
Correct sampling location
Correct test method
Proper calibration
Representative operating conditions
Quality assurance
Accurate calculations
Regulatory documentation
CEMS Requirements Under Rule 1134
Large turbines may have additional monitoring obligations.
Under Rule 1134, certain gas turbines 2.9 MW and larger at non-RECLAIM NOx facilities are subject to continuous monitoring provisions.
The rule requires applicable systems to monitor NOx and oxygen and also capture information such as:
Flow rate
Water/steam-to-fuel ratio where applicable
Operating time
Turbine output in MW
The CEMS requirements reference South Coast AQMD Rules 218, 218.1, 218.2 and 218.3.
That means Rule 1134 compliance can connect directly with:
CEMS Certification + QA/QC + RATA + CGA + Data Validation
CEMS vs. Source Testing
CEMS
Source Testing
Continuous monitoring
Periodic testing
Provides ongoing emissions data
Provides test-period emissions data
Used for applicable large turbines
Used where source testing is required
Requires QA/QC
Requires approved test procedures
May require certification
Requires proper field testing
Can identify changes over time
Provides a compliance snapshot
Depending on the turbine and regulatory requirements, a facility may need one or both approaches.
What Happens During a Gas Turbine Emissions Test?
A professional test program may include:
Step 1 — Pre-Test Review
Review:
Air permit
Turbine specifications
Fuel
Control equipment
Previous test results
Applicable Rule 1134 requirements
Step 2 — Test Planning
Determine:
Pollutants
Test methods
Operating conditions
Sampling location
Required test runs
Equipment
QA/QC
Step 3 — Equipment Preparation
Verify:
Calibration
Sampling equipment
Analyzers
Data systems
Gas standards
Flow measurement
Step 4 — Field Testing
Collect representative emissions data under applicable operating conditions.
Step 5 — Data Validation
Review:
Calibration data
Run data
QA/QC
Operating parameters
Calculations
Step 6 — Compliance Evaluation
Compare the results with applicable requirements.
Step 7 — Reporting
Prepare the technical source-test report and required documentation.
Common Rule 1134 Compliance Problems
1. High NOx
Potential causes include:
Combustion problems
Poor tuning
Control-system malfunction
Fuel changes
Catalyst problems
2. SCR Performance Problems
Catalyst degradation or improper ammonia control can affect emissions performance.
3. CEMS Problems
Analyzer drift, calibration issues or sampling-system problems can affect data validity.
4. Incorrect Operating Conditions
Testing at an inappropriate load may produce results that do not represent required compliance conditions.
5. Poor Documentation
Missing calibration, maintenance or testing records can create unnecessary compliance difficulties.
Rule 1134 Compliance Pros
✅ 1. Better NOx Control
Testing and monitoring help identify excessive NOx emissions.
✅ 2. Early Problem Detection
Emission testing can reveal problems before they become larger operational issues.
✅ 3. Improved Combustion Performance
Testing can help facilities understand turbine performance.
✅ 4. Better Compliance Documentation
Professional test reports create useful regulatory records.
✅ 5. Supports Environmental Goals
NOx reductions contribute to improved regional air quality.
✅ 6. Better Maintenance Decisions
Emission trends can provide an additional indicator of equipment condition.
Rule 1134 Compliance Cons / Challenges
❌ Testing Costs
Source testing requires specialized personnel, instruments and laboratory resources.
❌ Operational Coordination
The turbine may need to operate under specified conditions during testing.
❌ CEMS Investment
Large applicable turbines may require continuous monitoring systems.
📍 Facility Location ⚙️ Turbine Manufacturer & Model ⚡ MW Rating 🔥 Fuel Type 🛠️ Control Technology / SCR Information 📄 Current Permit 📊 Previous Test Report
Request a Rule 1134 Compliance Review Today
Test Your Emissions. Verify Your Compliance. Protect Your Operation.
Rule 1110.2 Compliance in California: Stationary Engine Testing, NOx, CO & VOC Requirements
Is your stationary engine compliant with California’s air-quality requirements?
If your facility operates a gaseous- or liquid-fueled stationary engine in the South Coast Air Quality Management District (South Coast AQMD), Rule 1110.2 may apply to your equipment.
The rule is designed to reduce NOx, VOC and CO emissions from regulated engines. The current South Coast AQMD rule was amended on November 3, 2023, and South Coast AQMD currently lists Proposed Amended Rule 1110.2 (PAR 1110.2) among rules in the proposal/amendment process.
For facility owners, plant managers and EHS professionals, this means engine testing, monitoring, recordkeeping and compliance planning should not be treated as an afterthought.
Rule 1110.2 California
What Is South Coast AQMD Rule 1110.2?
Rule 1110.2 – Emissions from Gaseous- and Liquid-Fueled Engines establishes emission and monitoring requirements for applicable engines.
The current rule states that its purpose is to reduce:
NOx — Nitrogen Oxides
VOC — Volatile Organic Compounds
CO — Carbon Monoxide
The rule generally applies to stationary and portable engines over 50 rated brake horsepower (bhp), subject to its applicability provisions and exemptions.
Important California compliance point
Rule 1110.2 is not a single statewide California rule. It is a South Coast AQMD rule, so facilities outside the South Coast AQMD jurisdiction must determine which local air-district requirements apply.
Why Rule 1110.2 Matters to Your Business
Stationary internal-combustion engines are used throughout California industry for:
Power generation
Natural-gas compression
Cogeneration
Industrial processes
Water and wastewater operations
Agricultural operations
Emergency/standby power
Other mechanical and electrical applications
Depending on the engine and operating conditions, emissions can include significant amounts of NOx, CO and VOCs.
That’s why regulatory agencies require facilities to demonstrate that applicable engines are operating within their permitted and regulatory limits.
Which Engines Can Be Subject to Rule 1110.2?
Potentially regulated equipment can include:
Natural Gas Engines
Used for generators, compressors, pumps and industrial equipment.
Biogas Engines
Engines operating on landfill gas or digester gas can have specific requirements.
Liquid-Fueled Engines
Certain stationary engines using liquid fuels may fall under the rule.
Large Industrial Engines
Large engines can trigger more extensive monitoring requirements.
Low-Use Engines
The rule contains specific provisions for engines operating less than 500 hours/year or using less than 1 × 10⁹ Btu/year of fuel, subject to the applicable requirements.
2026 Regulatory Update: Rule 1110.2 Remains Under Amendment Review
One of the most important things facility operators should know in 2026 is that South Coast AQMD currently lists Proposed Amended Rule 1110.2 as an active rulemaking item.
The PAR 1110.2 process was developed alongside proposed Rule 1110.3 for linear generators. South Coast AQMD’s rulemaking page contains draft documents and working-group materials from the process.
What does this mean for industry?
It means businesses should monitor regulatory developments rather than relying only on an old compliance checklist.
However, a proposed amendment should not be treated as an adopted requirement until officially adopted and effective.
Depending on the applicable engine category and compliance requirement, testing can involve:
NOx Testing
NOx is one of the primary pollutants regulated under Rule 1110.2.
CO Testing
Carbon monoxide provides important information about combustion performance and compliance.
VOC Testing
VOC emissions are also regulated, with applicable limits depending on the engine category.
South Coast AQMD maintains a specific source-test protocol for NOx, CO and VOC testing for stationary internal-combustion engines subject to Rule 1110.2.
Why Professional Engine Emissions Testing Matters
A stationary engine may appear to operate normally while still producing emissions above an applicable limit.
For example:
Engine running normally
↓
Combustion conditions change
↓
NOx/CO/VOC emissions increase
↓
Compliance test fails
↓
Corrective action + retesting
This is why proactive emissions testing can be valuable.
Rule 1110.2 Source Testing Requirements
For applicable source testing, the rule contains detailed requirements.
Among other provisions, applicable testing can require testing during:
Normal operation
Actual duty cycle
Peak load
Minimum practical load
The rule states that certain source testing must include at least 30 minutes during normal operation, plus NOx and CO testing at applicable peak and minimum loads, unless the permit limits operation to a defined load range.
Another important requirement:
The rule states that testing should occur at least 40 operating hours or one week after engine servicing or tuning, as applicable. It also prohibits pre-tests for compliance.
That means testing schedules need to be planned carefully.
Source-Test Protocol: Don’t Leave It Until the Last Minute
One of the biggest compliance mistakes is treating the source-test protocol as paperwork to complete immediately before testing.
Rule 1110.2 requires, for applicable tests, submission of a source-test protocol for written approval at least 60 days before the scheduled test date. The protocol must address items such as:
Engine identification
Permit/application information
Applicable emission limits
Test methods
Number of test runs
Operating loads
VOC sampling requirements
Parameters measured under the Inspection & Monitoring Plan
The rule also requires approval before testing.
That’s why early planning matters.
Protocol → Approval → Testing → Reporting
Testing Contractor Requirements
For applicable Rule 1110.2 source tests, the rule requires use of a contractor approved by the Executive Officer under the Laboratory Approval Program (LAP) for the necessary test methods.
South Coast AQMD also maintains its source-testing methods and procedures, including the dedicated Rule 1110.2 protocol.
Before hiring a testing company, verify:
Appropriate test-method approval
Relevant experience
Qualified personnel
Proper instrumentation
QA/QC procedures
Reporting capability
Familiarity with South Coast AQMD requirements
Source-Test Reporting
Testing doesn’t end when the instruments are removed from the stack.
For applicable Rule 1110.2 testing, the rule requires source-test reports to be submitted to the Executive Officer within 60 days of completion of the test.
A professional testing program therefore includes:
Planning → Field Testing → Data Validation → Calculations → Report Preparation → Submission
CEMS Requirements Under Rule 1110.2
Large engines may have additional continuous monitoring requirements.
The current rule requires NOx and CO CEMS for certain engines rated 1,000 bhp or greater and operating more than 2 million bhp-hours per calendar year.
CEMS can also be required at facilities with applicable engines having a combined rating of 1,500 bhp or greater at the same location and combined fuel usage exceeding 16 × 10⁹ Btu/year, subject to the rule’s provisions and exclusions.
The rule also requires applicable CEMS to comply with relevant requirements under Rules 218 and 218.1, including equipment specifications, certification, operation, recordkeeping, QA and reporting.
This connects Rule 1110.2 directly with CEMS compliance.
Rule 1110.2 also contains Inspection and Monitoring (I&M) requirements.
Applicable operators may need an approved I&M Plan covering items specified by the rule.
South Coast AQMD also provides:
Combustion Gas Periodic Monitoring Protocol
Calibration recordkeeping forms
Periodic monitoring forms
Stability-check forms
Linearity/interference records
through its Rule 1110.2 compliance resources.
Portable Analyzer Testing
Portable combustion analyzers can play an important role in Rule 1110.2 compliance.
South Coast AQMD states that portable-analyzer engine tests required under the I&M provisions must be conducted by a person who has completed an approved training program and received South Coast AQMD certification.
This is important because a portable-analyzer measurement is not simply a matter of taking a reading.
Proper procedure matters.
The person conducting the test needs appropriate training, equipment, calibration and documentation.
Emergency Standby Engines: A Common Compliance Misunderstanding
Many businesses assume:
“It’s an emergency generator, so air-quality rules don’t apply.”
That’s not necessarily correct.
South Coast AQMD identifies an emergency backup generator as a standby ICE or turbine for non-utility power generation that operates no more than 200 hours per year and is used for emergency power failure or routine testing/maintenance, subject to the applicable requirements.
Rule 1110.2 also contains exemptions for certain emergency standby engines limited by permit conditions to 200 hours or less per year, along with other specified categories.
The permit condition matters.
Don’t assume that simply calling an engine an “emergency generator” automatically exempts it from every requirement.
Rule 1110.2 service provider in California
Rule 1110.2 Compliance: Pros & Cons
Advantages of Proactive Compliance
1. Early Problem Detection
Testing can identify elevated emissions before a regulatory deadline.
2. Better Engine Performance
Combustion testing can identify operating problems.
3. Reduced Compliance Risk
Regular monitoring provides better visibility into emissions.
4. Better Documentation
Professional reports create an organized compliance record.
5. Improved Maintenance Planning
Emission trends can help identify equipment problems.
6. Better Preparation for Rule Changes
Facilities that maintain accurate emissions data can make better upgrade decisions.
Potential Challenges
Testing Costs
Professional source testing requires equipment, personnel and laboratory/analytical resources.
Operational Coordination
The engine may need to operate at specific loads during testing.
Protocol Lead Time
Applicable protocols may need regulatory approval well before testing.
Failed Tests
An exceedance can require corrective action and potentially additional testing.
CEMS Costs
Large applicable engines may require continuous monitoring systems.
Recordkeeping
Compliance requires maintaining appropriate records and documentation.
What Happens If an Engine Fails?
A failed test shouldn’t be ignored.
A typical corrective approach is:
1. Identify the Cause
Check:
Fuel system
Air/fuel ratio
Ignition
Engine condition
Catalyst
Control equipment
Operating load
Maintenance history
2. Correct the Problem
Tune, repair or modify the equipment as appropriate.
CEMS-CGA, RATA & Certification in California: 2026 Compliance Guide for Industrial Facilities
Is your Continuous Emissions Monitoring System actually producing data that regulators can rely on?
For many industrial facilities in California, having a CEMS (Continuous Emissions Monitoring System) installed is only the beginning. Depending on the applicable permit, air-district rules, and federal requirements, the system may need initial certification, quality assurance testing, Cylinder Gas Audits (CGA), Relative Accuracy Test Audits (RATA), ongoing QA/QC and periodic reporting.
For facilities regulated by the South Coast Air Quality Management District (South Coast AQMD), Rules 218, 218.2 and 218.3 establish important requirements for CEMS administration, certification, performance specifications and QA/QC. South Coast AQMD’s current rule book lists Rule 218 as amended March 5, 2021, and Rules 218.2 and 218.3 as amended September 2, 2022.
This makes professional CEMS Certification, CGA and RATA testing an important part of an industrial facility’s compliance strategy.
CEMS Certification California
What Is CEMS?
CEMS stands for Continuous Emission Monitoring System.
A CEMS continuously measures one or more emission parameters from an industrial source.
Depending on the application, it can monitor:
NOx
SO₂
CO
CO₂
Oxygen (O₂)
Flow rate
Moisture
Other regulated pollutants
A CEMS can continuously generate emissions data that may be used for compliance demonstrations, reporting and regulatory decision-making.
South Coast AQMD explains that CEMS can be required to continuously demonstrate compliance with permitted concentration limits and, for applicable RECLAIM systems, automatically report mass emissions.
The key point:
A CEMS is not automatically a compliance instrument simply because it is installed.
It must meet the applicable certification and performance requirements.
What Are CEMS Certification, RATA and CGA?
These three terms are closely connected but have different purposes.
CEMS Certification
Demonstrates that the monitoring system meets applicable regulatory performance and quality requirements and can function as an official data-reporting instrument.
RATA — Relative Accuracy Test Audit
Compares CEMS measurements against an applicable reference method to determine whether the CEMS is sufficiently accurate.
CGA — Cylinder Gas Audit
Challenges the CEMS with certified calibration/audit gases to verify analyzer response and measurement performance.
Together, they help answer:
Can regulators trust the emissions data being produced by the CEMS?
Why Is CEMS Compliance Important in California?
Industrial facilities may have strict emission limits for pollutants such as NOx, SO₂ and other contaminants.
When CEMS data are used to demonstrate compliance, inaccurate monitoring can create a serious problem.
A facility may believe it is compliant while the monitoring system is:
Drifting
Out of calibration
Producing invalid data
Experiencing excessive downtime
Outside required performance specifications
Operating outside its approved span range
Missing required QA/QC tests
South Coast AQMD Rule 218.3 provides requirements addressing CEMS performance, QA/QC, out-of-control periods and alternative data acquisition.
2026 California CEMS Regulatory Landscape
California’s CEMS requirements continue to evolve through local air-district rules, federal requirements and pollutant-specific monitoring programs.
For South Coast AQMD-regulated facilities, Rules 218, 218.2 and 218.3 remain central to CEMS requirements.
South Coast AQMD’s FY 2026–27 budget and objectives also continue to identify CEMS Certification as a compliance activity, demonstrating that CEMS review and certification remain an active regulatory function.
2026 takeaway:
CEMS should be treated as an ongoing compliance program—not a one-time installation project.
CEMS Certification: What Does the Process Involve?
For a new or modified CEMS, certification can involve multiple stages.
South Coast AQMD’s current CEMS application package describes a certification pathway that includes:
CEMS plan, where applicable
CEMS application
Quality Assurance Plan (QAP)
Initial District approval
Certification source-test protocol
District review/approval of the protocol
Certification source testing
Certification source-test report
District approval/final certification
Continuing QA/QC and periodic testing
Once certified, the CEMS remains subject to requirements involving maintenance, modifications, outages, records and periodic QA/QC testing such as RATAs.
This is why certification should be planned early.
A facility should not wait until the CEMS installation is complete before considering the certification process.
RATA Testing Company
What Is a RATA?
RATA = Relative Accuracy Test Audit.
A RATA evaluates how closely the CEMS measurement agrees with an applicable reference method.
In simple terms:
CEMS Result vs. Reference Method Result
The closer they agree, the more confidence regulators can have in the CEMS data.
South Coast AQMD defines relative accuracy in terms of the difference between CEMS-generated data and reference-method results, including the confidence coefficient.
A typical RATA may involve:
CEMS operating
↓
Reference-method sampling
↓
Simultaneous measurements
↓
Multiple test runs
↓
Statistical evaluation
↓
Relative accuracy calculation
↓
Pass / Fail determination
Why Is RATA Testing So Important?
Imagine your CEMS reports:
NOx = 45 ppm
But an approved reference method produces significantly different results.
Which number should regulators trust?
That’s exactly why RATA exists.
A successful RATA provides evidence that the CEMS is accurately measuring the emissions parameter within the applicable performance specification.
South Coast AQMD provides dedicated technical guidance for RATA-related issues, including RATA outliers and mass-emissions RATA for non-concurrent concentration and flow measurements.
What Is a CGA?
CGA = Cylinder Gas Audit.
During a CGA, the CEMS is challenged using gases with known certified concentrations.
Under federal EPA QA procedures, applicable CGA testing uses a zero-level gas and two upscale audit levels within specified ranges, with repeated injections designed to challenge the measurement system.
The basic concept is:
Known Gas → CEMS → Measured Value → Compare
If the CEMS response is outside the applicable tolerance, corrective action may be required.
RATA vs. CGA
Feature
RATA
CGA
Full Name
Relative Accuracy Test Audit
Cylinder Gas Audit
Main Purpose
Compare CEMS against reference method
Check analyzer response using known gases
Reference Method
Yes
No, uses certified gases
Field Sampling
Usually required
Gas challenge
Statistical Evaluation
Yes
Yes, according to applicable procedure
Frequency
Depends on applicable rule/program
Depends on applicable rule/program
Certification Role
Important
Important QA/QC component
Failure Response
Investigation/correction/retest as required
Calibration/correction/retest as required
Important:
Don’t assume that a CGA replaces a RATA in every regulatory program.
The applicable rule, permit and federal/state monitoring requirements determine what is required.
How Often Is RATA Required?
There is no single testing frequency for every California CEMS.
The interval depends on the applicable program.
For example, EPA’s Procedure 1 for applicable gas CEMS requires a RATA at least once every four calendar quarters, subject to the applicable provisions. It also provides for CGA-based quarterly QA in certain circumstances.
Other programs can have different requirements.
Your facility’s permit and applicable regulation control.
This is especially important for facilities operating under:
Title V
South Coast AQMD rules
RECLAIM-related requirements
Federal NSPS requirements
Federal NESHAP/MACT requirements
40 CFR Part 60
40 CFR Part 75
Pollutant-specific monitoring programs
RATA Certification
What Happens When a CEMS Fails QA/QC?
This is where CEMS compliance becomes particularly important.
A failed QA/QC test can result in an out-of-control period under applicable requirements.
South Coast AQMD Rule 218.3 provides that CEMS data generated during an applicable out-of-control period can be considered invalid for emission quantification in a compliance demonstration.
The facility may then need to:
Identify the problem
Correct the CEMS
Perform the required QA/QC test
Establish when valid data resumes
Evaluate affected data
Use an approved alternative data-acquisition method where applicable
Complete required reporting
This can become expensive if the issue is discovered too late.
Common Reasons CEMS Fail RATA or QA/QC
1. Analyzer Calibration Problems
Incorrect calibration can create measurement bias.
2. Sampling-System Problems
Leaks, condensation, contamination or sample-line problems can affect readings.
3. Span Range Problems
The selected span must be appropriate for the applicable requirements.
4. Moisture Interference
Moisture can affect certain monitoring systems if not properly accounted for.
5. Stratification
Non-uniform pollutant concentrations across the stack can affect comparison between the CEMS and reference method.
6. Flow Issues
Poor flow measurement can affect mass-emission calculations.
7. Aging Components
Sensors, analyzers, pumps and other components can degrade over time.
8. Poor Maintenance
A CEMS requires continuous attention.
CEMS Certification Is Not “Set It and Forget It”
A common mistake is:
Install CEMS → Get certified → Forget about it.
That’s not how an effective compliance program works.
After certification, facilities must continue managing:
Calibration + QA/QC + RATA + CGA + Maintenance + Data Availability + Records + Reporting
South Coast AQMD’s certification materials specifically state that certified CEMS remain subject to scheduled and unscheduled maintenance, outages, modifications, records/reporting and ongoing QA/QC.
2026 Update: CEMS Technology Is Expanding
CEMS requirements are also evolving for specialized pollutants.
A notable example is ethylene oxide (EtO).
South Coast AQMD entered into a July 2025 Memorandum of Understanding with Parter to help develop performance specifications, verification test protocols and implementation guidance for an EtO CEMS certification program. The MOU runs through December 31, 2026 unless extended.
This demonstrates an important industry trend:
Continuous monitoring is expanding beyond traditional NOx/SO₂ applications.
Facilities with specialized toxic-air-contaminant requirements should monitor regulatory developments closely.
CEMS and Environmental Compliance Are Becoming More Data-Driven
Modern air-quality compliance increasingly depends on continuous data.
Instead of relying only on periodic stack tests, regulators can use monitoring systems to evaluate:
Hourly emissions
Daily emissions
Operating conditions
Exceedances
Data availability
Control-device performance
Long-term trends
South Coast AQMD’s CEMS application materials state that applicable CEMS can continuously monitor compliance and automatically signal exceedances, breakdowns and out-of-control periods.
Accurate data is therefore a compliance asset.
Pros of CEMS, RATA, CGA & Certification
✅ 1. Continuous Compliance Visibility
CEMS provides ongoing emissions information rather than occasional snapshots.
✅ 2. Early Problem Detection
Abnormal emissions can potentially be identified faster.
✅ 3. Stronger Compliance Documentation
Certified monitoring data can support regulatory reporting where applicable.
✅ 4. Better Process Control
Operators can use emissions information to improve process operation.
✅ 5. Reduced Compliance Uncertainty
Routine QA/QC helps identify monitoring problems before they become major issues.
✅ 6. Better Long-Term Data
Historical CEMS information can help identify trends.
RATA Testing, Cylinder Gas Audit
Challenges / Cons
❌ Higher Initial Cost
Installing a compliant CEMS can require significant capital investment.
❌ Ongoing Maintenance
Analyzers, sampling systems and data-acquisition equipment require regular attention.
❌ QA/QC Requirements
RATA, CGA and other tests require planning and qualified personnel.
❌ Data Availability Issues
CEMS downtime can create compliance complications.
❌ Technical Complexity
CEMS involve instrumentation, electronics, sampling systems, software and regulatory requirements.
❌ Regulatory Changes
Changes to rules or permits can require modifications to the monitoring program.
But the cost of maintaining a reliable CEMS is usually easier to manage than discovering a monitoring failure during a compliance deadline.
Which Industries May Need CEMS Services?
Potential applications include:
Power & Energy
Power plants
Cogeneration facilities
Distributed generation
Manufacturing
Chemical plants
Metal processing
Cement
Glass
Manufacturing facilities
Petroleum & Chemical
Refineries
Petrochemical plants
Process facilities
Waste & Combustion
Waste-to-energy
Incineration
Thermal processing
Industrial Boilers
Large boilers
Steam generators
Process heaters
Other Regulated Sources
Facilities with permit or regulatory requirements for continuous monitoring.
EES can help bring these pieces together into one coordinated compliance program.
South Coast AQMD maintains a Laboratory Approval Program (LAP) under which laboratories and source-testing firms are evaluated method-by-method for personnel, equipment, documentation, QA and other criteria. Facilities should verify that the testing provider and applicable methods meet the requirements of their specific program.
Boiler Certification, Tune-Up & Testing in California: 2026 Compliance Guide for Industrial & Commercial Facilities
Is your boiler operating efficiently—and is it meeting California air-quality requirements?
For industrial, institutional and commercial facilities, boiler compliance is more than keeping equipment running. Depending on the boiler size, fuel, location, permit and applicable air district rules, facilities may need certification, periodic tune-ups, emissions testing, recordkeeping and other compliance activities.
In Southern California, South Coast AQMD Rules 1146, 1146.1 and 1146.2 are particularly important for boilers, steam generators, process heaters and certain water heaters. South Coast AQMD’s current rule book lists Rule 1146 as amended in 2020, Rule 1146.1 as amended in 2018, and Rule 1146.2 as amended in 2024.
For facility owners and EHS managers, the key question is not simply:
“Does my boiler work?”
It is:
“Can my boiler demonstrate compliance with the applicable air-quality requirements?”
This is where professional Boiler Certification, Tune-Up and Testing services become valuable.
What Is Boiler Certification, Tune-Up & Testing?
These are related but different compliance activities.
Boiler Certification
Certification generally involves demonstrating that applicable equipment meets the requirements of the governing air-district rule or certification program.
For example, South Coast AQMD maintains a Certified Boilers List under Rule 1146.2, with the current equipment list updated December 30, 2025.
Boiler Tune-Up
A tune-up evaluates and adjusts combustion performance to help the boiler operate properly while controlling emissions.
Boiler Emissions Testing
Testing measures actual emissions—such as NOx, CO and oxygen—using the applicable regulatory test method.
NOx is particularly important because it contributes to ozone and smog formation.
South Coast AQMD states that combustion sources are among the sources of NOx emissions in the region, and its Rule 1146.2 amendments were designed to achieve significant NOx reductions.
For businesses, this means boiler operation can have both:
Facilities operating older boilers should therefore monitor rule developments rather than assuming today’s requirements will remain unchanged.
Boiler Testing Company
2026 Update: Rule 1146.2 Has Important Zero-Emission Requirements
South Coast AQMD amended Rule 1146.2 on June 7, 2024, establishing a transition toward zero-emission equipment for certain water heaters, boilers and process heaters.
A major 2026 milestone is:
January 1, 2026
South Coast AQMD’s 2026 compliance-deadline guidance states that certain Type 1 units ≤400,000 Btu/hr and qualifying instantaneous water heaters ≤200,000 Btu/hr installed in new buildings must comply with zero-emission limits.
The practical implication is significant:
Boiler and water-heating equipment planning is changing.
Facilities installing or replacing equipment should evaluate applicable requirements before purchasing equipment, rather than discovering a compliance issue after installation.
What Does a Boiler Tune-Up Actually Do?
A professional tune-up focuses on combustion performance.
Depending on the equipment and applicable rule, the process can include checking:
Fuel-to-air ratio
Oxygen concentration
Carbon monoxide
Stack temperature
Flame condition
Burner operation
Draft
Combustion-air supply
Fuel pressure
Operating load
Control settings
South Coast AQMD’s Rule 1146 tuning procedures specifically address operating the equipment at a representative firing rate and recording combustion parameters such as stack temperature, oxygen and CO.
For example, poor combustion can contribute to elevated CO or inefficient operation.
Too much excess air can also reduce combustion efficiency.
Too little combustion air can create incomplete combustion and elevated CO.
A properly performed tune-up seeks an appropriate combustion balance while maintaining safe operation.
South Coast AQMD’s tuning procedures explicitly state that tuning must not create unsafe conditions or violate applicable safety requirements, manufacturer specifications or other relevant regulations.
When Is Boiler Tune-Up Required?
This depends on the applicable rule and the specific unit.
For example, Rule 1146.1 contains a tune-up option for certain qualifying units with annual heat input of 18,000 therms or less. Units using this option must be tuned at least twice per year, at intervals of four to eight months, according to the prescribed or manufacturer’s procedure, with records maintained for a rolling 24-month period.
That does not mean every California boiler requires two tune-ups every year.
This distinction is important.
The applicable:
Rule + Unit Size + Fuel + Operating History + Permit
determine what is required.
Boiler Emissions Testing: What Is Measured?
Depending on the applicable regulatory requirement, testing may include:
NOx
Nitrogen oxides are a major regulatory focus for combustion equipment.
CO
Carbon monoxide helps evaluate combustion performance and may be subject to emission limits.
Oxygen
O₂ measurements can be used for combustion analysis and, depending on the rule, emissions corrections.
Other Parameters
Depending on the source, testing may also evaluate:
Stack temperature
Exhaust flow
Fuel consumption
Heat input
Operating load
Control-device parameters
Boiler Tune-Up Services
How Often Does a Boiler Need Emissions Testing?
There is no single California-wide testing interval.
The frequency depends on the applicable rule and equipment.
For example, South Coast AQMD Rule 1146 provides specific compliance-testing provisions. Under one provision, certain units at or above 10 MMBtu/hr have a three-year compliance determination interval, while certain units from 5 to below 10 MMBtu/hr have a five-year interval.
Other requirements may apply depending on the boiler category, compliance option and regulatory program.
Don’t assume your neighbor’s testing schedule applies to your boiler.
Boiler Certification vs. Boiler Testing
These terms are often confused.
Certification
Testing
Demonstrates equipment meets a certification requirement
Measures actual emissions
Often associated with specific equipment categories
Usually associated with operating equipment
Can apply to equipment models/configurations
Measures field performance
May be required before installation/operation
May be periodic
Documentation-based
Data/measurement-based
South Coast AQMD maintains certified equipment lists to help businesses identify equipment that meets applicable requirements. The current Rule 1146.2 certified-boiler list was updated December 30, 2025.
Why Boiler Testing Can Fail
A boiler doesn’t necessarily fail because it is mechanically broken.
Compliance problems can come from:
1. Incorrect Burner Settings
Improper combustion settings can increase emissions.
2. Excessive CO
Incomplete combustion can produce elevated CO.
3. Excess NOx
Combustion conditions may result in NOx above an applicable limit.
4. Poor Maintenance
Dirty burners, fouled surfaces or degraded components can affect combustion.
5. Incorrect Operating Conditions
A test performed under the wrong load or process conditions may not demonstrate compliance.
6. Aging Equipment
Older boilers may have difficulty meeting newer emissions requirements.
7. Inadequate Documentation
Even when equipment performs properly, missing records can create compliance complications.
The Cost of Ignoring Boiler Compliance
For a facility manager, a boiler compliance problem can quickly become an operational problem.
Potential consequences may include:
Failed emissions test
↓
Investigation
↓
Corrective maintenance
↓
Retesting
↓
Production disruption
↓
Additional engineering expense
↓
Possible regulatory enforcement
The exact consequences depend on the applicable air district, rule, permit and circumstances.
The smarter approach is preventive compliance.
Pros of Professional Boiler Certification, Tune-Up & Testing
✅ 1. Helps Demonstrate Regulatory Compliance
Measured data and proper documentation provide evidence of compliance with applicable requirements.
✅ 2. Improves Combustion Performance
A properly tuned boiler can operate more effectively.
✅ 3. Helps Identify Problems Early
Testing can reveal elevated emissions before they become a larger compliance issue.
✅ 4. Supports Better Maintenance Decisions
Testing data can help identify when burners, controls or other components need attention.
✅ 5. Reduces Compliance Surprises
A planned testing program is safer than waiting for a regulatory deadline.
✅ 6. Supports Equipment Planning
Testing can help determine whether an older boiler can continue operating within applicable limits.
Challenges / Cons
Professional testing also involves costs and planning.
Challenge
Potential Impact
Testing cost
Budget required
Tune-up cost
Technician/engineering expense
Production coordination
Boiler access may require scheduling
Retesting
Additional cost if results are unsatisfactory
Documentation
Requires organized recordkeeping
Regulatory changes
Existing equipment may face future requirements
Equipment upgrades
Older boilers may require modernization
But there is a difference between a compliance cost and an unexpected compliance crisis.
Planning usually gives a facility more options.
Which Industries Need Boiler Compliance Services?
Potential clients include:
Manufacturing
Food processing
Pharmaceutical manufacturing
Chemical manufacturing
Automotive
Aerospace
Textile
Paper
Plastics
Institutional
Hospitals
Universities
Schools
Government facilities
Commercial
Hotels
Large commercial buildings
Laundry facilities
Food-service operations
Industrial
Refineries
Industrial processing plants
Warehouses with process heating
Energy facilities
The exact requirements depend on the equipment and jurisdiction.
Boiler Tune-Up Services
Why Hospitals and Large Facilities Should Pay Special Attention
Hospitals, universities and large commercial buildings often rely heavily on boilers for:
Steam
Hot water
Heating
Sterilization
Laundry
Process applications
A boiler compliance issue can therefore affect more than emissions.
It can affect:
Operations + Energy Use + Maintenance + Compliance
This makes proactive testing particularly valuable.
How EES Helps With Boiler Certification, Tune-Up & Testing
A boiler test should not be treated as an isolated laboratory exercise.
Your testing company should understand:
The boiler → the combustion process → the air district → the rule → the test method → the compliance limit
That’s the difference between simply collecting emissions data and building a useful compliance program.
2026 Boiler Compliance Checklist
Before your next boiler test or tune-up, ask:
Is the boiler properly permitted/registered?
What is the rated heat-input capacity?
What fuel does it use?
Which California air district regulates the facility?
Which boiler rule applies?
Is certification required?
Is a tune-up required?
When was the last tune-up?
When was the last emissions test?
What are the applicable NOx limits?
What are the applicable CO requirements?
Is a source-test protocol required?
Is agency notification/approval required?
Are operating conditions specified?
Are records current?
Has the boiler or burner been modified?
Has the applicable rule changed?
2026: Why Facilities Should Review Their Boiler Compliance Program Now
The regulatory environment is moving toward lower-emission and zero-emission technologies.
South Coast AQMD’s 2026 rule-development work includes proposed amendments to Rules 1146 and 1146.1.
At the same time, Rule 1146.2 has already introduced significant zero-emission requirements for certain equipment categories, including requirements taking effect January 1, 2026.
This creates a strategic question for facility owners:
Should you continue maintaining the existing boiler, upgrade it, replace the burner, or transition to another technology?
Current emissions-testing data can help answer that question.
Don’t Wait for a Failed Boiler Test
A failed compliance test is often the worst time to start investigating your boiler.
Instead:
Test → Analyze → Tune → Verify → Document
This approach gives facility managers a better opportunity to identify problems before they become emergencies.
Need Boiler Certification, Tune-Up & Testing in California?
EES Can Help Your Facility Stay Ahead of Compliance Requirements
Air Toxics Testing in California: Multimetals, Hexavalent Chromium & Dioxin/Furans — 2026 Compliance Guide
California continues to maintain one of the most comprehensive air-toxics regulatory frameworks in the United States. For facilities that emit or may emit toxic air contaminants (TACs), accurate emissions measurement is increasingly important for permitting, compliance demonstrations, health-risk assessments and regulatory reporting.
For industrial facilities, Air Toxics Testing can involve specialized testing for multimetals, hexavalent chromium (Hex Chrome), dioxins/furans and other toxic pollutants. The exact testing obligation depends on the facility’s permit, applicable air-district rules, source type, pollutant and regulatory program. CARB specifically notes that California compliance-testing requirements vary by local agency and may use CARB, U.S. EPA or other published test methods.
With regulatory activity continuing through 2026, now is an important time for facilities to review their air-toxics testing programs.
Why Is Air Toxics Testing Important in California?
Toxic air contaminants are different from ordinary criteria pollutants because the regulatory focus is strongly connected to potential human-health impacts.
California’s AB 1807 program established a framework for identifying and controlling toxic air contaminants. CARB describes the program as a two-step process involving risk identification and risk management.
California’s identified toxic-air-contaminant list includes substances such as:
Hexavalent chromium
Arsenic compounds
Cadmium compounds
Lead compounds
Nickel compounds
Mercury compounds
Manganese compounds
Dioxins and furans
Benzene
Formaldehyde
Other toxic compounds
CARB’s current TAC information identifies hexavalent chromium and chlorinated dioxins/furans among substances for which no threshold level has been identified in its listing.
That is why reliable emissions data matters.
You cannot effectively manage what you have not accurately measured.
California Air Toxics Testing
What Is Air Toxics Testing?
Air Toxics Testing is the measurement and laboratory analysis of hazardous or toxic pollutants emitted from an industrial process, combustion source, control device or other emission point.
Depending on the facility, testing can include:
Multimetals Testing
Measurement of multiple metals potentially present in industrial emissions, such as:
Arsenic
Cadmium
Chromium
Lead
Nickel
Manganese
Mercury
Antimony
Beryllium
Cobalt
Selenium
Other regulated metals
Hexavalent Chromium Testing
Specialized measurement of Cr(VI) emissions from applicable chromium-related processes.
Dioxin/Furan Testing
Measurement of chlorinated dioxins and furans, which can be associated with certain combustion and industrial processes.
CARB identifies dioxins as toxic air contaminants and notes that they can originate from waste incineration, some chemical manufacturing and other industrial sources that burn fuel.
2026 California Air Toxics Regulatory Updates
1. South Coast AQMD Is Updating Toxic-Air-Contaminant Requirements
One of the most important 2026 developments is continued work on Proposed Amended Rule 1401 — New Source Review of Toxic Air Contaminants.
South Coast AQMD’s 2026 rulemaking materials show workshops and draft rule language during 2026, with proposed changes addressing new toxic air contaminants identified by California’s Office of Environmental Health Hazard Assessment and revisions to health values for existing compounds.
What does this mean for facilities?
A pollutant that previously received little attention could become more important when:
Toxicity information changes → health values change → risk calculations change → permitting/testing requirements may change.
Facilities should therefore avoid assuming that an old emissions profile automatically represents today’s regulatory requirements.
2. Rule 1469 and Hexavalent Chromium Requirements Have Become More Stringent
Hexavalent chromium remains one of California’s most closely scrutinized toxic air contaminants.
South Coast AQMD amended Rule 1469 — Hexavalent Chromium Emissions from Chromium Electroplating and Chromic Acid Anodizing Operations on December 5, 2025. The rule incorporates more stringent requirements associated with CARB’s Chromium ATCM, including lower emission limits and increased source-testing requirements for applicable operations.
South Coast AQMD’s regulatory advisory states that beginning January 1, 2026, functional chrome-plating facilities face more stringent requirements, including lower limits for applicable Tier III tanks and source testing every two years for Tier III tanks.
This makes Hex Chrome source testing particularly important for applicable chrome-plating and chromic-acid-anodizing facilities.
3. Source-Test Protocols Are Becoming More Important
For applicable Rule 1469 facilities, the source-testing process isn’t simply a matter of showing up with sampling equipment.
South Coast AQMD’s Rule 1469 materials specify situations where a source-test protocol must be submitted in advance. For certain Tier III tanks beginning January 1, 2026, the protocol must be submitted at least 60 days before the first applicable source test for approval.
Waiting until the last minute can create avoidable scheduling and compliance problems.
4. Air Toxics “Hot Spots” Activity Continues in 2026
California’s AB 2588 Air Toxics “Hot Spots” Program remains an important part of the regulatory landscape.
South Coast AQMD’s current 2026 AB 2588 activity includes approved health-risk assessments, facility public-notification activity and updated guidance documents. The District lists, for example, a January 2026 update to its emission-factor reference-source template and 2026 health-risk-assessment activity.
For facilities subject to AB 2588 requirements, emissions information can ultimately feed into health-risk assessments and risk-management decisions.
This is another reason why reliable source-test data is valuable.
Air Toxics Testing (Multimetals, Hex Chrome & Dioxin/Furans) in California | Energy Environmental Solutions, Inc.
Multimetals Testing: Why It Matters
Industrial processes can release several metals simultaneously.
A facility might not have a compliance concern involving only one metal. Depending on the source and applicable requirements, the emissions profile could contain multiple regulated metals.
Multimetals testing can therefore provide a more comprehensive picture of emissions.
Potential applications include:
Metal processing
Metal melting
Foundries
Plating
Aerospace manufacturing
Welding-related operations
Chemical manufacturing
Waste processing
Combustion processes
Manufacturing operations
Industrial furnaces
South Coast AQMD’s Regulation XIV contains multiple rules addressing toxic and non-criteria pollutants, including metal-related rules and Rule 1469 for hexavalent chromium.
Hexavalent Chromium Testing
Hexavalent chromium, commonly written as Cr(VI) or Hex Chrome, deserves special attention.
It can be associated with processes including:
Hard chrome plating
Decorative chrome plating
Chromic acid anodizing
Certain chromium-containing coating operations
Other applicable industrial processes
The regulatory environment around chrome operations has tightened.
South Coast AQMD’s 2025 Rule 1469 amendment incorporated the state’s more stringent chromium requirements, including phase-out provisions, lower emission limits and more frequent source testing for applicable operations.
If your facility handles chromium, don’t rely on an old testing schedule without checking the current rule.
Dioxin & Furan Testing
Dioxins and furans are another category where specialized testing is essential.
CARB explains that dioxins can be produced through certain combustion activities and chemical manufacturing processes and identifies dioxins as toxic air contaminants.
Potentially relevant sources can include:
Waste combustion
Incineration
Certain thermal processes
Chemical manufacturing
Industrial combustion
Certain metal-processing activities
Other processes identified by the applicable regulatory program
Dioxin/furan testing generally requires highly specialized sampling and laboratory analysis.
This is not a routine emissions test.
The sampling, sample handling, analytical procedures and quality-control requirements must be carefully planned.
What Can a Professional Air Toxics Test Evaluate?
Depending on the applicable regulation and test method, a testing program may evaluate:
Testing can help determine whether an air-pollution-control device is achieving its intended performance.
5. Improved Regulatory Preparedness
Facilities that maintain current emissions information are better positioned to respond to permit modifications and regulatory changes.
6. Greater Confidence for Management
Facility managers can make decisions using measured data instead of assumptions or outdated emission factors.
Challenges and Cons of Air Toxics Testing
Challenge
What It Can Mean for Facilities
Cost
Specialized testing and laboratory analysis can be expensive
Complexity
Toxic-air-contaminant methods can be technically demanding
Scheduling
Testing may need coordination with production
Downtime
Some tests require specific operating conditions
Protocol Requirements
Certain programs require advance protocol preparation/submission
Laboratory Requirements
Applicable rules may require qualified or approved laboratories
Corrective Action
Elevated results may require investigation or additional testing
South Coast AQMD operates a Laboratory Approval Program under which independent laboratories/source-testing firms are evaluated method-by-method for personnel, equipment, documentation, QA and related criteria.
Why Choosing the Right Testing Company Matters
Air toxics testing is not simply about collecting a sample.
The complete process can involve:
Regulatory Review
↓
Test Protocol Development
↓
Sampling Plan
↓
Field Testing
↓
Sample Handling
↓
Laboratory Analysis
↓
QA/QC Review
↓
Engineering Calculations
↓
Compliance Report
A mistake at any stage can affect the usefulness of the final results.
That’s why industrial facilities should work with an experienced environmental testing provider familiar with California air-district requirements and source-testing procedures.
How EES Helps Industries With Air Toxics Testing
Energy Environmental Solutions, Inc. (EES) can help industrial facilities manage specialized air-toxics testing programs.
1. Multimetals Testing
EES can support testing programs for applicable metal emissions, including multi-metal analysis.
2. Hex Chrome Testing
For applicable chromium-related operations, EES can support hexavalent chromium emissions testing and associated compliance programs.
3. Dioxin/Furan Testing
EES can support specialized testing programs involving dioxins and furans for applicable industrial sources.
4. Test Protocol Development
Before testing begins, EES can help develop a protocol addressing:
Applicable regulations
Sampling methods
Sampling locations
Operating conditions
Analytical methods
QA/QC
Reporting requirements
5. Source Testing
EES can coordinate and perform applicable source-testing services based on the requirements of the relevant air district and permit.
6. Laboratory Coordination
Specialized air-toxics testing requires appropriate analytical capabilities. EES can coordinate applicable laboratory analysis and documentation.
7. Compliance Reporting
The final objective isn’t just a laboratory result.
It is a defensible compliance record.
8. Regulatory Support
EES can help facilities understand how their testing program fits within applicable California air-quality requirements.
Industries That May Need Air Toxics Testing
Potential clients include:
Metal Plating Facilities
Chrome Plating Facilities
Aerospace Manufacturers
Metal Fabrication Facilities
Foundries
Chemical Manufacturers
Waste Processing Facilities
Industrial Combustion Facilities
Manufacturing Plants
Coating Operations
Refineries
Power Generation Facilities
Thermal Processing Facilities
Incineration Operations
Other Facilities Subject to TAC Requirements
CARB’s Air Toxics Tool notes that different industries can be associated with different toxic pollutants and that the listed substances are not necessarily a complete list for every industry.
2026 Air Toxics Compliance Checklist
Before your next test, ask:
☑ What toxic pollutants could my source emit?
☑ What does my current permit require?
☑ Does my air district require source testing?
☑ Is multimetals testing required?
☑ Is Hex Chrome testing applicable?
☑ Are dioxin/furan emissions relevant to my process?
☑ Is a source-test protocol required?
☑ Does the protocol require advance agency approval?
☑ Is a qualified/approved laboratory required?
☑ Is my previous test still representative?
☑ Has the equipment or production process changed?
☑ Have applicable rules changed for 2026?
Why You Should Not Wait Until the Testing Deadline
Imagine discovering two weeks before your regulatory deadline that:
Your sampling ports need modification.
Your old protocol is no longer appropriate.
The applicable test method has changed.
Your laboratory needs advance scheduling.
Your facility cannot achieve the required operating condition.
The air district requires advance protocol submission.
Now your testing deadline becomes a business problem.
Early planning turns regulatory pressure into a manageable project.
For specialized testing such as Hex Chrome or Dioxin/Furan, advance coordination is especially important.
Stack Testing
Why 2026 Is the Right Time to Review Your Air Toxics Program
California’s toxic-air-contaminant regulatory environment continues to evolve.
South Coast AQMD’s 2026 rulemaking schedule includes activity surrounding Rule 1401, toxic-air-contaminant health values and additional toxic-emission controls.
At the same time, Rule 1469 requirements for applicable chromium operations have become more stringent, with increased attention to source testing.
The practical takeaway for facility owners and EHS managers is simple:
Don’t manage today’s emissions with yesterday’s compliance assumptions.
Review your:
Permit + Rules + Equipment + Testing Schedule + Test Methods + Emissions Data
Turn Air Toxics Compliance Into a Competitive Advantage
Compliance is often treated as a cost.
But smart companies can look at it differently.
Reliable emissions testing can help you:
Identify problems early → improve process control → reduce compliance uncertainty → maintain better records → respond faster to regulatory changes
That’s a much stronger position than waiting for an inspection or regulatory deadline.
Natural Gas Engines
Advantages of Proactive Compliance
Testing Costs
Manufacturing
Energy & Power
Oil & Gas
Water & Wastewater
Agriculture
Commercial & Institutional
Don’t Wait Until Your Engine Fails a Compliance Test
Review Rule 1110.2 applicability
