36 Fires, One Common Thread: Refrigerant Nobody Could Vouch For

Our VP of Sales, Don Sobocinski, posted a refrigerant safety bulletin on methyl chloride that’s worth expanding on. His point: you should be able to trace every cylinder you open back to a source that will stand behind it. A report out of South Korea this month shows exactly what happens when nobody asks that question.

What Korea’s fire agency found

On September 2, South Korea’s National Fire Agency announced that it had tied a run of air conditioner fires to illegal refrigerant blends containing R-40, better known as methyl chloride. Beginning August 3, working with the National Fire Research Institute, fire investigation bodies in Seoul and Gyeonggi, and the Gyeongnam Fire Department, investigators found trimethyl aluminum inside the outdoor units of the affected systems.

Over five years they identified 36 fires in which air conditioner refrigerant is suspected as the cause, including 11 that had originally been logged under a different cause and were reclassified once investigators knew what to look for. The trend is the part that should get your attention.

Suspected refrigerant-caused air conditioner fires recorded by the Republic of Korea National Fire Agency.

Here is the number that matters most to anyone who turns a wrench. Of those 36 fires, 17 happened during removal or recharge operations. That’s 47.2 percent. Another 13 occurred while the system was running, four while it sat idle, and two under unspecified conditions.

Nearly half of these fires started with a technician working on the equipment. All figures are current as of the National Fire Agency’s September 2026 announcement.

It was sold as R-22

This is the detail that should land hardest for US contractors.

R-22 is an A1 refrigerant, nonflammable, and it’s still in a very large installed base of older equipment. Korea halted R-22 production in 2023 on ozone grounds, the price climbed, and cheap illegal blends started moving through online sales platforms and direct-from-overseas purchases. According to the National Fire Agency, the people making those blends mix in R-40 and sell it in containers labeled R-22.

The agency also noted that you cannot tell the illegal blend from the real product by looking at it.

Now look at the US. Production and import of R-22 ended here on January 1, 2020. Everything legitimately available today is recovered, reclaimed, or pre-2020 stock. Same shrinking supply, same upward price pressure, same installed base that still needs service, same marketplaces. The conditions that produced 36 fires in Korea are not exotic. They are the conditions in our market right now.

Why R-40 in an HVAC system is so dangerous

R-40 is methyl chloride, also called chloromethane. Industry used it as a refrigerant in the 1920s and 30s and abandoned it because it is toxic and flammable. It is also aggressively corrosive to aluminum, and that is where the real hazard comes from.

The chloromethane reacts with the aluminum components in the outdoor unit, including the rotor and the piping, and forms trimethyl aluminum. Korean regulation classifies trimethyl aluminum as a Class 3 hazardous material: it can ignite spontaneously on contact with air and reacts violently with water to generate flammable substances. It’s a liquid at room temperature, and it accumulates at the low points of the circuit.

The failure mode is what makes this so ugly. On the first charge, the system may run perfectly normally. The hazardous compound forms gradually during operation. Then someone comes back to disassemble or recharge the unit, cuts into the tubing, exposes the accumulated liquid to air and moisture, and it ignites.

The system becomes its own ignition source, and the person standing in front of it is the technician.

Two injuries from this summer make the point. In July, a fire investigator collecting evidence at a house fire in Jinju suffered second-degree burns on both hands from a spark at the outdoor unit’s refrigerant inlet. In June, in Ganghwa, Incheon, a man in his seventies was severely injured in an explosion while charging gas into an outdoor unit and had to be evacuated by medical helicopter.

Same substance, a different label every time

Korea is not an isolated case. R-40 has surfaced three separate times in the last fifteen years, and it has worn a different name each time. If you have been following this story and the refrigerant designations seem to keep changing, that is because they do.

The 2011 and 2012 case is the one most people in this industry remember. Blends of R-40 and R-22 were falsely labeled and sold as R-134a, and they caused explosions and deaths in several countries. It hit the refrigerated container trade hard enough to ground thousands of reefers worldwide.

Last December, Environment and Climate Change Canada warned that counterfeit cylinders sold as R-410A contained a mixture of R-32 and R-40. Genuine R-410A to the AHRI 700 standard is a roughly 50/50 blend of R-32 and R-125, with the R-125 serving as a suppressant so the finished blend classifies as nonflammable. Swapping R-40 in for that suppressant does the opposite of what the formulation is designed to do. ECCC reported the product arrived in generic packaging in non-refillable cylinders, and noted that exposing a system charged with it to air or moisture, which is exactly what servicing does, could produce a strong acid and explosive reactions. No incidents were reported in Canada.

Now Korea, with R-40 blended into R-22 cylinders and sold as R-22.

Three incidents, three different refrigerant designations on the label, one substance inside. The label is the only thing in this chain you cannot verify by looking at it.

This is a counterfeiting problem, not a flammability problem

It’s worth being precise here, because the two get conflated constantly.

Every refrigerant class in service today has an established, safe handling protocol. A1, A2L, A3, and natural refrigerants all have documented charge limits, ventilation requirements, leak detection expectations, and service procedures under ASHRAE Standards 15 and 34 and the model codes. Those protocols work because the technician knows what is in the system.

Counterfeit product destroys that assumption. A technician who believes he has a nonflammable A1 refrigerant and actually has an unlisted, toxic, corrosive substance isn’t following the wrong protocol. He has no protocol at all, and neither does the equipment.

Korea’s own fire agency made the same distinction. It stated plainly that the problem does not involve all air conditioning refrigerants, and that regularly imported product subject to quality control is considered safe. The alert is about low-cost illegal blends moving through unverified channels.

The variable that matters is verified identity, not flammability class.

What to actually do about it

Both agencies published guidance alongside their findings, and it lines up almost word for word. ECCC told the Canadian trade to inspect their refrigerant supply, keep the supply chain accountable, and purchase only from authorized distributors. Korea’s National Fire Agency told contractors and consumers to be suspicious of refrigerant priced well below market, to avoid firms using cylinders that carry no quality certification mark, to use only formally registered installers, and to record and keep the installer’s details so responsibility can be established if something goes wrong. Neither agency said anything about flammability class. Both said the same thing about provenance.

Buy through a supply chain that answers the phone

Authorized distributors, known manufacturers, documented chain of custody. If a seller can’t tell you who produced the gas and where, that is your answer. Online marketplaces, direct-from-overseas orders, and cash deals on pallets of surplus refrigerant are exactly where this material moved in Korea.

Ask for the certificate of analysis, then read it

A real CoA ties a specific lot to specific test results analyzed to AHRI Standard 700. At minimum you should see refrigerant identification by gas chromatography, composition against the nominal blend, moisture, acidity, high boiling residue, non-condensables, particulates, and chlorides. R-40 isn’t within the scope of AHRI 700 at all, which is the point. A proper composition analysis shows you what’s actually in the cylinder rather than what the label claims.

If a supplier produces a generic sheet with no lot number traceable to the cylinder in your truck, treat the product as unknown.

Trust the price signal

Counterfeiting exists because legitimate refrigerant costs money. Between the R-22 phaseout and the HFC phasedown under the AIM Act, supply is constrained and prices reflect it. A quote well below market is not a deal you found. It’s a question you haven’t asked yet.

Test when anything doesn’t add up

Unknown provenance, an odd pressure-temperature relationship, unexplained repeat compressor failures, a cylinder that doesn’t match its paperwork. Pull a sample and have it analyzed to AHRI 700 before it goes into a customer’s equipment.

If you suspect contamination, stop

Do not operate the equipment. Do not cut into the system. Do not recover into a cylinder holding known-good refrigerant, and do not vent anything, which is prohibited under Section 608 of the Clean Air Act regardless of what’s in the circuit. Isolate the unit, quarantine and clearly mark any suspect cylinders, contact the equipment manufacturer, and report suspected counterfeit or illegally imported product to EPA.

Decontaminating a system that may contain trimethyl aluminum is not a field procedure. Korea’s data says nearly half these fires start during service work. Do not become the next data point.

The enforcement picture is getting sharper

EPA and the Department of Homeland Security co-chair an Interagency Task Force on Illegal HFC Trade, with CBP, DOJ, DOD, and State participating. EPA’s criminal enforcement program launched Operation: Disrupt HFCs in February 2024 to go after the illegal supply chain directly, and the first criminal prosecution under the AIM Act involved a defendant charged with smuggling refrigerant across the southern border and reselling it online.

Buying from an accountable source protects your techs and your customers. It also keeps you clear of a body of law being enforced more aggressively every year.

Where we fit

FluoroFusion is an EPA-certified reclaimer and a manufacturer of refrigerants under the Arctic Eagle and FluoroFusion brands, with an AHRI 700-certified laboratory at our facility in Clayton, North Carolina. Every batch we produce is analyzed in that lab before it ships, and the results are documented and traceable to the cylinder.

We also test refrigerant we didn’t make. If you have a cylinder you can’t vouch for, or a system behaving in a way you can’t explain, our lab runs full AHRI 700 analysis and modified AHRI 700 liquid-phase analysis on customer samples.

That’s a far cheaper afternoon than the alternative.

Reach our lab team at lab@fluorofusion.com or find sample submission details at fluorofusion.com/labservices.

Sources

• National Fire Agency announcement, September 2, 2026 — Republic of Korea official portal

• South Korea, fires linked to illegal refrigerants — ZeroSottoZero, September 8, 2026

• Lethal R40 refrigerant blamed for Korean AC fires — Cooling Post, September 2, 2026

• Fake R410A refrigerant mixed R40 with R32 — Cooling Post, December 9, 2025

• Operation: Disrupt HFCs — US EPA

• Enforcement Alert: EPA Targeting Illegal Imports of Hydrofluorocarbon Super-Pollutants — US EPA

• Homeowners and Consumers: Frequently Asked Questions — US EPA, HCFC-22 phaseout

Disclaimer

This post is general industry information, not technical or legal advice. Always follow equipment manufacturer instructions, applicable codes, and EPA regulations. A laboratory analysis report describes the sample submitted and is not a safety certification of any equipment or system.