EPA SF6 Gas Regulations: A (relatively) concise primer

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SF6 used as Arc Quenching medium in electric power systems

EPA SF6 Gas Regulations: A (relatively) concise primer

The EPA regulates greenhouse gas emissions under their Greenhouse Gas Reporting Program (GHGRP) and have recently decided to place renewed emphasis on SF6.

SF6 is one of the worst greenhouse gases in terms of its global warming impact. In fact, it is 25,000 times more damaging to the environment than carbon dioxide (CO2). Adding to its potency is sulfur hexafluoride’s atmospheric lifetime of 3,200 years which makes this gas one of the worst atmospheric pollutants on paper. So why would we use one of the most potent greenhouse gases when we are trying to limit the atmospheric concentration of greenhouse gases?

Sulfur hexafluoride is critical to several industries, including electric power systems, where SF6 is used as an arc quenching medium and electrical insulator. Sulfur hexafluoride, first produced in 1901 by Henri Moissan and Paul Lebeau, is critical to today’s cutting-edge semiconductor industry. And while other industries can switch to alternative gases with lower GWP, there is no good substitute for SF6 in many critical applications.

The shifted EPA SF6 gas regulations will make smaller companies more responsible now

For a long time, smaller companies did not have an obligation to report on SF6 based on estimated leak rates if they had less than 17,820 tons of carbon installed. However, a recent change to triggers are reducing the threshold by 90% making many more companies, including semiconductor, electrical distribution, and even glass manufactures responsible for reporting.

Under the EPA emissions reduction program, more attention is being paid to SF6 management because of data that shows that over the past 20 years, there has been a 2x increase in usage of this potent gas, as determined by the atmospheric concentration of sulfur hexafluoride. The EPA has realized that they do not currently have an understanding of exactly how much of this potent greenhouse gas is being utilized and how much is being released into the atmosphere.

The Greenhouse Gas Reporting Program (GHGRP) is an EPA program that requires reporting of greenhouse gas (GHG) data and other relevant information from large GHG emission sources, fuel, and industrial gas suppliers, and CO2 injection sites in the United States. This article discusses proposed changes to GHGRP by the EPA and why these changes are being implemented. 

What is the EPA changing about SF6 monitoring and reporting?

EPA SF6 gas regulations 1

The EPA is becoming increasingly concerned with the inaccuracies they are finding in their reports around sulfur hexafluoride inventory and emissions, especially since SF6 is such a potent greenhouse gas. The records regarding inventory that the EPA is receiving are wrong. In order to have a better understanding of actual emissions the Environmental Protection Agency is looking to find a better way to receive data that is accurate. Furthermore, the EPA wants to harmonize its data in accordance with the AIM act.

The proposed rule changes do not limit the GHG emissions of covered sources, nor does it require sources to take steps to reduce their GHG emissions. This is strictly a reporting rule that creates a large data set that the EPA uses to assess trends and make other policy decisions.

What is most interesting about the proposed changes is the ways in which these changes will impact companies that have not historically had an obligation to report. Semiconductor companies, data centers, and small utility companies are going to be affected by these changes as the EPA’s list of NAICS codes is expanded. Let’s dive right into the primary changes.

In this blog, we are specifically focusing on the major changes that were made to the following subparts based on relevance and impact:

EPA SF6 Gas Regulations: Subpart I (Electronics Manufacturing) 

EPA is proposing new thresholds for reporting, a new emissions factor calculation method, and new GHG impact calculations for F-gases used during semiconductor manufacturing. Additionally, the EPA is looking for manufacturers of semiconductors to start stack testing for emissions. And there is also an added requirement that purge flow indicators be calibrated each time a vacuum pump is serviced or exchanged.

These changes are to ensure the EPA understands the full scope of greenhouse gas emissions during the manufacturing process. Because there are several gases with high global warming potential used both during the fabrication process and emitted as a result of those gases being used, the EPA is looking to clarify calculations around reporting use of these gases. This rule change updates the emissions factors and calculations for gases used during semiconductor manufacture, including sulfur hexafluoride.

Two of the proposed calculation methods are closely based on the methods that have been used historically to calculate emission factors for processes that use multiple gases: the ‘‘all-input gas method and the ‘‘dominant gas method’’. The emission factors calculated using these methods are also expected to be reasonably robust except under certain circumstances discussed further in this section. To increase the robustness of the emission factors calculated using these methods under those circumstances, the EPA is proposing to modify the methods to avoid input gas emission factors greater than 0.8 for processes that use multiple gases.

Why a new calculation is needed for emissions factors

Both the all-input gas method and the dominant gas method can provide an emissions factor greater than 0.8. In actuality, the emissions factor calculated using these 2 methods can exceed 1. An emissions factor that exceeds 1 violates the conservation of mass and thus provides inaccurate results.

To avoid an input gas emission factor greater than 0.8 when multiple gases are used, the EPA is proposing to introduce an additional calculation method. The modified methods would attribute emissions of each F–GHG used as an input gas to that input gas until the mass emitted equaled 80 percent of the mass fed into the process, that is until the 1–U factor equaled 0.8. The methods would then assign the remaining emissions of the F– GHG either to the dominant input gas as a by-product (in the dominant gas method) or to the other input gases as a by-product in proportion to the quantity of each input gas used in the process (in the all-input gas method).

EPA SF6 Gas Regulations: Subpart DD (Electrical Transmission) 

EPA SF6 Gas Regulations Subpart DD


The impact of this rule change to electric utilities cannot be understated. If you were not tracking SF6 before, you are more than likely to be required to going forward, even if you are a small regional utility. To quote the EPA:

“We are proposing to remove the existing nameplate capacity threshold, and instead provide a calculation method for facilities to estimate total annual GHG emissions for comparison to the 25,000 metric tons of CO2 threshold. These changes align with proposed changes to redefine the source category to include equipment containing ‘‘fluorinated GHGs (F–GHGs), including but not limited to sulfur hexafluoride or and perfluorocarbons (PFCs)’’

So what does the EPA mean by this? In the past, electric utilities could simply look at their installed nameplate of SF6 and if the listed capacity was under 17,820lbs, then they knew instantly they did NOT have to report. Now the EPA is requiring that every company run an emissions calculation (DD-3) to determine their actual emissions from sulfur hexafluoride and PFC’s.  If their emissions are greater than or equal to 25,000 mtCO2e then they must report under 98. This means they must also pay special attention to leaking electrical equipment.

If you don’t have a system for tracking the variables in the DD-3 equation, (e.g. decrease in insulating gas inventory, disbursements of insulating gas, increase in nameplate capacity, etc.), it is impossible to prove to the EPA that you do or don’t have to report under 98. For smaller players in the electric power industry, the EPA is clear, you now have to produce data to prove that you are not required to report.

Companies that have sulfur hexafluoride-containing assets must work on tracking and calculating emissions from all on-site emissions sources in order to:

  • Prove that gross emissions are under 25,000 mtCO2e and therefore prove that they do not need to report under part 98.
  • Understand that gross emissions are OVER 25,000 mtCO2e and therefore report under part 98.

EPA SF6 gas regulations and emissions data

EPA SF6 Gas Regulations: Subpart W (Petroleum and Natural Gas Systems)

In its latest round of proposed revisions, the EPA states that it is seeking to improve data quality and require reporting for new emission sources. These proposed changes will almost certainly result in higher emissions estimates for petroleum and natural gas facilities than in previous years.

Sources that will be covered by reporting requirements for the first time include: pneumatic controller venting; abnormal emission events that are unaccounted for with existing reporting requirements (i.e., “other large release events” such as storage wellhead leaks and well blowouts); and acid gas removal vents.

Also, the EPA is proposing to revise existing requirements for emissions from several sources within this source category, including glycol dehydrator vents, liquids unloading, atmospheric storage tanks, associated gas flaring, and equipment leaks.

The EPA is trying to understand the full impact the petroleum and natural gas industries are having from all potential sources of emissions. This update is trying to incorporate sources of greenhouse gas emissions overlooked to this point.

EPA SF6 Gas Regulations: Subpart SS (Electrical Equipment Manufacturers or Refurbishment)

Similar to Subpart I, the revision to Subpart SS sets the reporting threshold for SF6 to 25,000 mtCO2e for electrical equipment manufactures and refurbishment.

The proposed revisions would remove the consumption-based threshold at 40 CFR 98.451 and instead require facilities to estimate total annual GHG emissions for comparison to the 25,000 metric tons of CO2 threshold by introducing a new equation, equation SS–1.

“Subpart SS currently requires facilities that have total annual purchases of SF6 and PFCs that exceed 23,000 pounds to report. Therefore, we are proposing to revise the applicability threshold to align with the proposed revisions to require reporting of additional F–GHG beyond SF6 and PFCs.”

“Potential reporters would be required to account for the total annual purchases of all insulating gases, and multiply by the GWP for each F–GHG and the emission factor of 0.10 (or 10 percent).”

Based on the SS-1 equation, electrical equipment manufacturers and refurbishment must track the total annual purchases of insulating gas, as well as understanding the weight fraction of fluorinated GHG in the insulating gas if the insulating gas is a gas mixture and the GWP for that gas or mixture.

While this rule update looks to simplify the reporting threshold, it can complicate things for companies that did not have a reporting responsibility in the past. Accurate record-keeping and inventory management will be key to accurate reporting in this case.

EPA SF6 Gas Regulations: Subpart OO (Suppliers of Industrial Greenhouse Gases) 

The EPA is proposing changes to improve our understanding of end-uses of GHGs and to better understand GHG supply. For subpart OO, EPA is proposing to require suppliers of nitrous oxide (N2O), saturated PFCs, and SF6 to identify the end uses for which the N2O, SF6, or PFC is used, and the quantities of N2O, SF6, or each PFC transferred to each end use, if known.

This requirement would help to inform the development of GHG policies and programs by providing information on N2O, sulfur hexafluoride, and PFC uses and their relative importance, where the GWP-weighted quantities of these compounds that are supplied annually to the U.S. economy are relatively large, and where the identities and magnitudes of the uses of these compounds are less well understood.

While some may claim confidentiality being an issue with disclosing the required information, all of the information required by the EPA reporting is already publicly available data through other agencies and entities. So the requirement to report isn’t going anywhere.

See more on the confidentiality issue here.

EPA SF6 Gas Regulations: Subpart NN (Suppliers of Natural Gas and Natural Gas Liquids) 

Similar to Subpart OO, the EPA is requiring Liquified Gas manufacturers and importers to identify the end use for each gas. The EPA is proposing to require at 40 CFR 98.416(k) that suppliers of N2O, saturated PFCs, and SF6 identify the end uses for which the N2O, SF6, or PFC is used and the aggregated annual quantities of N2O, SF6, or each PFC transferred to each end use if known.

EPA SF6 Gas Regulations: Subpart VV (Geologic Sequestration of Carbon Dioxide) 

EPA SF6 gas regulations subpart VV


The EPA is trying to grasp the brand-new industry of carbon sequestration. They have created a new source category, geologic sequestration of CO2 in association with EOR operations; and identify end uses of GHGs that are not currently accounted for in existing reporting, for consideration in future policy development.

Geologic sequestration is the process of injecting CO2, captured from an industrial (e.g., steel and cement production) or energy-related source (e.g., a power plant or natural gas processing facility), into deep subsurface rock formations for long-term storage.

This is an entirely new industry, so understanding its impact on total carbon emissions is critical to understanding its significance in reducing carbon emissions. The factors the EPA is requiring those that fall under this category to report the following from Clause 8 of CSA/ANSI ISO 27916:2019 (incorporated by reference, see § 98.7):

  • The mass of CO2 received by the CO2-EOR project.
  • The mass of CO2 loss from the CO2-EOR project operations.
  • The mass of native CO2 produced and captured.
  • The mass of CO2 produced and sent off-site.
  • The mass of CO2 loss from the EOR complex.
  • The mass of CO2 stored in association with CO2-EOR.

If you fall into this category, it is worth reaching out to the EPA to find out more about this reporting requirement.

EPA SF6 Gas Regulations and the impacts on cement, glass, iron, and steel industries

For the cement, glass, iron and steel Industries: the EPA proposes to collect more detailed data to verify reported emissions and, in some instances, calculate back-estimates of process emissions.

The EPA proposes requiring affected cement facilities to report emission equations inputs to the agency. They also seek to add this requirement for cement production to back-estimate reported GHG emissions.

For glass production, the EPA proposes to require facilities to report the “annual quantity of glass produced by the facility in tons, by glass type, from each continuous glass melting furnace and from all furnaces combined.”

For iron and steel production, the EPA proposes to require facilities to report the specific type of unit that is an emission source, as well as the annual production capacity and operating hours of the unit.

The EPA is also proposing to streamline monitoring requirements for iron and steel production under 40 C.F.R. Part 98, Subpart Q, giving reporters several options to account for carbon dioxide uptake in produced metal materials.

Some potential new sectors

The EPA’s proposal solicited input on whether it should expand the GHGRP rule to include new source categories, including energy consumption, ceramics production, calcium carbide production, coke calcining, CO2 utilization, and others. With the commenting period now close, these have now been added as the new sectors. The EPA has pledged to continue using GHGRP data to evaluate potential new regulations for reporting sectors. Be on the lookout for an update on this in 2023 as the EPA receives feedback.

One additional noteworthy statement in the latest revisions to GHGRP is that in compliance with the AIMS act, there are 12 data elements that are not eligible for confidential treatment and will be publicly released.  This is one of the primary areas of focus in the industry comments back to the EPA. You can find the table of those data points here.

How can YOU manage EPA SF6 gas regulations properly?

The world is changing. Global warming is forcing us into consistent action. And history shows that the pattern of increased reporting requirements will continue. With all of these changes, it is easy to become overwhelmed. To get a handle on these EPA changes, we recommend that all companies look into the following:

  • Improved Accountability and Documentation
  • Training of field personnel to ensure zero loss during any gas handling event
  • Traceability of events including Emergent Loss events, leaking GIE, Repair/Replacement of leaking GIE
  • Equipment upgrades of recovery equipment which allow for zero-emission practices
  • Scale calibration and Mass Flow Meter implementation
  • Self Sealing fittings that are zero-emission
  • Improved leak detection processes
  • Cylinder accountability
  • MFG improvements of GIE with <1% annual leakage rate
  • Improve Maintenance Programs

Compliance starts with a comprehensive strategy, developing a culture of compliance, and taking clear action to provide accurate and comprehensive reporting.

Getting started on the compliance journey

How can you stay in compliance, gather all of the right information, and manage your reports and data? Trakref is here to help. Our software allows organizations of any size to track, monitor, and report their use of sulfur hexafluoride and its emissions in one simple platform. Most importantly with work with companies that track greenhouse gas emissions worldwide and must generate reports not just in the U.S. but for strict E.U. requirements as well.

Trakref will help you with tracking everything, including EPA SF6 gas regulations

As a software company, we have worked tirelessly to develop a solution that meets the needs of companies that need SF6 compliance. Trakref’s software provides comprehensive reports in minutes, not days. Giving your ESG managers, asset managers, and end users the tools they need to get the job done efficiently.

Trakref provides the ability to:

  • Track cylinder history & use
  • Push-button access to Subpart DD reports
  • Measure installed capacity
  • Corporate-wide leak rate
  • Cylinder rental/history/use/locator
  • Service event transaction report
  • Produce an annual greenhouse gas emissions report based on data entered 

If you need help with EPA SF6 gas regulations or any other regulatory or compliance topic, reach out today.

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