The history of refrigerants

To effectively manage your business’s refrigerant inventory, it is helpful to understand how potent greenhouse gases became ubiquitous in the first place, and which cleaner alternatives are now available. We thought providing a bit of context on the history of refrigerants would be helpful.

Do environmentally friendly refrigerants exist?

Natural refrigerants such as ammonia and propane have been used for hundreds of years, and are among the most environmentally friendly, efficient options. When used as a refrigerant or in air conditioners, ammonia is highly effective at absorbing substantial amounts of heat from its surroundings. Propane emits less carbon monoxide than gasoline, produces fewer particles than diesel, and contains no Sulphur (a contributor to acid rain). Both have a global warming potential (GWP) between 0 and 4, a stark difference from some of the first synthetic refrigerants, which registered global warming potential (GWP) in the tens of thousands. Though they are better options from an environmental standpoint, the quest for optimal, human-safe, climate-safe refrigerants continues.

History of refrigerants

Early (pre-1900s) refrigeration was centered around the often-treacherous practice of hauling ice from frozen lakes and rivers. Safer options were sought, and the first refrigerants (including ammonia) were used, but with the advent of the use of chemicals to cool, these new contraptions were known to be a dangerous alternative, proving fatal when leaks or fires occurred. People would often place their refrigerators in their backyards, to keep the toxic chemicals at a distance. This led engineer Thomas Midgley Jr., in 1928, to develop the first synthetic refrigerant chlorofluorocarbon (CFC) R-12, or “Freon,” as a safer, non-flammable, and non-toxic solution. Following R-12’s widely marketed success, hydrochlorofluorocarbon (HCFC) R-22 was developed, followed by others including hydrofluorocarbon (HFC) R-134a, which are still used globally in common applications like refrigerators and vehicle air conditioners.

Global efforts to mitigate 

By the 1970s, scientists had discovered that the use of these CFCs and, to a lesser extent, HCFCs, were causing serious damage to the ozone layer. In 1987, 197 countries ratified the Montreal Protocol, a global agreement to phase out the production and consumption of ozone-depleting substances. CFCs R-11 and R-12 were phased out in the 1990s and replaced with the less-damaging HFCs. But these are still potent greenhouse gases, and in 2016, the Kigali Amendment was added to the Montreal Protocol. 

The Amendment called for countries to cut their HFC production and consumption by more than 80 percent over the next 30 years, with staggered deadlines for different economic capacities and infrastructure. While the EU F-Gas Regulation of 2014 began phasing out HFCs on an accelerated schedule in EU countries, under the Kigali Amendment, other developed nations were not required to begin until 2019 (or later), and developing nations were given even more time. The U.S. government did not enact a phase down or ratify the Kigali Amendment until 2022, and thus has less time remaining to meet their mandate of an 85% phase down by 2036. 

The US Climate Alliance, a bipartisan group now numbering 25 U.S. governors, has committed to reducing greenhouse gas emissions (including refrigerants) in line with the goals set by the 2015 Paris Agreement, wherein 196 governments agreed to work to keep the world’s average temperature well below rising to 2°C above what it had been before the Industrial Revolution. 

 Lingering threats, emergent solutions 

These efforts are essential to meeting longer term mitigation goals, but near-term threats also require immediate action.  While HFCs are still in the midst of being phased out, the costs of maintaining the systems they require will continue to rise if they are not replaced by a viable alternative. And though the phase outs have been effective in halting production of new toxic refrigerants, they do not yet include mandates to destroy the vast stores that already exist. As a result, they are still in use on a global scale, or are sitting in aging storage containers that will at some point decay. Once these gases, which have a GWP much higher than carbon dioxide, leak into the atmosphere, there will be no way to remove them.   

As the process of destroying and phasing out toxic refrigerants continues, a larger push is being made to revert to the use of natural refrigerants (such as hydrofluoroolefins [HFO]) that have been developed to have a lower GWP and no ozone-depleting potential. With these measures, accompanied by advancements in technology and more robust safety measures, industries are adopting a future-thinking climate perspective and are increasingly able to commit to sustainable, cost-effective practices.  


Emission reductions are considered permanent if they are not reversible. In some projects, such as forestry or soil preservation, carbon offset credits are issued based upon the volume of CO2 that will be sequestered over future decades—but human actions and natural processes such as forest fires, disease, and soil tillage can disrupt those projects. When that happens, the emission reductions claimed by the project are reversed.

The destruction of halocarbon does not carry this risk. All destruction activities in Tradewater’s projects are conducted pursuant to the Montreal Protocol , which requires “a destruction process” that “results in the permanent transformation, or decomposition of all or a significant portion of such substances.” Specifically, the destruction facilities Tradewater uses must meet or exceed the recommendations of the UN Technology & Economic Assessment Panel , which approves certain technologies to destroy halocarbons, including the requirement that the technology achieve a 99.99% or higher “destruction and removal efficiency.” Simply put, this means that Tradewater’s technologies ensure that over 99.99% of the chemicals are permanently destroyed. During the destruction process, a continuous emission monitoring system is used to ensure full destruction of the ODS collected.


Some carbon offset projects necessarily rely on estimations or assumptions when calculating the emission reductions from project activities. Forestry projects, where developers make assumptions about the carbon that will be sequestered over future decades if trees are conserved, are a perfect example. Such projects sometimes result in an overestimation of the environmental benefit of the project.

Tradewater’s halocarbon projects avoid the issue of overestimation by consistently conducting extremely precise testing and measurement of the amount of refrigerant destroyed in each project.

  • Every container of ODS that Tradewater destroys is weighed by a third-party using regularly calibrated scales. The ODS is then sampled by a third-party and analyzed by an accredited refrigerant laboratory to determine its species and purity. These two steps combine to ensure that credits are issued only for the precise volume and type of refrigerant destroyed.
  • The destruction facilities that Tradewater uses continuously monitor the incineration process during destruction events to ensure that over 99.99% of the ODS is destroyed. This monitoring is mandated by regulatory protocols and is part of the verification process to which projects are subjected.
  • Tradewater accounts for the project emissions created during the collection, transport, and destruction of ODS, and the number of offsets issued is reduced by a corresponding amount. The protocols that we use also build in other reductions to account for substitute chemicals that will be used to replace the destroyed refrigerants. Tradewater publishes this information in the documentation for all its ODS destruction projects. These documents outline how the material was obtained, the project emissions calculations, the test results, and the amount and type of ODS chemicals destroyed, among other information.
  • Additionality

    It is a basic requirement of all carbon offset projects that the underlying project activities are additional. “Additional” means that the projects would not happen in the absence of a carbon market. Tradewater’s halocarbon projects simply would not happen – and the gases would be left to escape into the atmosphere – without the sale of the resulting carbon offset credits. This is because there is no mandate to collect and destroy these gases. It is still permissible to buy, sell, and use halocarbons that were produced before the ban. There are other reasons halocarbon destruction projects are additional:

    • There are no incentives or financial mechanisms to encourage halocarbon destruction. According to the International Energy Agency and United Nations Environment Program, “there is rarely funding nor incentive” to recover and destroy ozone depleting substances in storage tanks and discarded equipment. And collecting, transporting, and destroying halocarbons is time-intensive and expensive. The burden to collect and destroy these gases therefore remains prohibitive outside of carbon offset markets—meaning that if organizations like Tradewater do not do this work, nobody else will.
    • Countries are not focused on the need to collect and destroy halocarbons. The Montreal Protocol has been celebrated as a success because of its production ban. This success, however, ignores the legacy gases produced before the ban and is a blind spot for government regulators. In the U.S., for example, the Environmental Protection Agency (EPA) developed a Vintaging Model in the 1990s to estimate the quantify of ozone depleting substances left in circulation. Based on the inputs and assumptions put into the model, the EPA predicted that no CFCs would be available for recovery beyond 2020 in the United States. But this prediction did not prove accurate. Tradewater has collected and destroyed more than 1.5 million pounds of CFCs globally in recent years and continues to identify thousands of pounds per week.
    • International carbon accounting standards do not require corporations to measure or track emissions tied to halocarbons, and refrigerants are specifically excluded from Science Based Targets initiative (SBTi) commitments. These commitments derive from emissions reporting under the GHG Protocol, which requires companies to report on emissions only from new generation refrigerants, such as hydrofluorocarbons (HFCs), but does not establish any obligation to report inventories or emissions of refrigerants still in use, such as CFCs and HCFCs. All these factors combine to make Tradewater’s carbon offset projects highly additional. As Giving Green, an initiative of IDinsight, concluded: “Tradewater would not exist without the offset market, so this element of additionality is clearly achieved.” The case for additionality is not so clear for some other project types, such as forestry and landfill gas carbon projects. For example, some forests are already being conserved for their beauty, or for use as parks, and generate carbon offset credits only because those conservation efforts do not yet have full formal protection in place to avoid deforestation in the future. Similarly, methane from landfills can be used to make electricity or captured as compressed natural gas, thereby creating additional revenue streams to support the activities, beyond the sale of carbon credits.