US HFC phasedown proceeds as states mull potential bans on substitutes

SAN ANTONIO (ICIS)–The US programme that will phase down the use of hydrofluorocarbons (HFCs) in refrigerants and blowing agents used In polyurethanes will hit some major milestones in the upcoming months – while states consider broad bans on fluorinated materials that could encompass the new chemicals that will replace them, hydrofluoroolefins (HFOs).

The US and other countries in the world are phasing down HFCs because they are exceptionally powerful greenhouse gases.

Worldwide, the global phasedown of HFCs should prevent the planet’s temperatures from rising by as much as half a degree Celsius, according to the Environmental Protection Agency (EPA).

UPCOMING MILESTONES
The US adopted a phasedown schedule as part of the American Innovation and Manufacturing (AIM) act, which became law earlier in the decade.

The Environmental Protection Agency (EPA) intends to finalise the technology transitions rule no later than 7 October, said Margaret Sheppard, environmental scientist at the EPA. She made her comments at the Polyurethanes Technical Conference, held by the Center for the Polyurethanes Industry (CPI).

The EPA should meet that deadline even if the US government shuts down at the end of September, she said.

Implementation of the phasedown will then proceed.

Sheppard expects implementation will go much smoother for the polyurethanes industry than those involved with refrigeration and air conditioning.

The polyurethanes industry has been preparing for the phasedown for several years by developing acceptable blowing agents and by developing formulations that are compatible with those new new blowing agents.

HFC PHASEDOWN SCHEDULE
The next big step takes place in 2024, when US regulations will call for a big decline in the amount of the amount of HFCs that the nation can consume and produce. That amount will be 60% of a baseline established by a formula in the AIM law.

The following table shows the phasedown schedule.

Year	% of baseline
2022-2023	90%
2024-2028	60%
2029-2033	30%
2034-2035	20%
2036 and after	15%

Source: EPA

In some cases, a suitable replacement for HFCs has yet to be found, Sheppard said. The one polyurethane application that falls into this group is structural composite foam for marine and trailer use.

In fact, the EPA is describing the process as a phasedown because there could still be some cases where no alternative to HFCs can be found.

STATE PFAS BANS COULD INCLUDE HFOS
The polyurethane industry has been relying on HFOs as a replacement for HFCs because they are exceptionally weak greenhouse gases and they do not threaten the ozone layer.

However, some governments could adopt broad definitions and bans of per- and polyfluorinated alkyl substances (PFAS) that could include HFOs, said Ian Choiniere, director, product advocacy for the CPI.

These definitions would go beyond those of the EPA, which do not include HFOs as PFAS, he said.

The US state of Maine signed into law such restrictions that could ban HFOs in 2030, Choiniere said.

Minnesota is another US state that could impose a similar ban in 2032, Choiniere said.

Maine has since implemented a legislative working group that would look into the rulemaking process, he said. That opens up the possibility of the state considering the implications of such a ban and developing exceptions to it.

Minnesota is has not begun the rulemaking process, so that also opens up the possibility of exceptions, Choiniere said.

FOREVER CHEMICALS
The state restrictions come amid growing concerns about PFAS being forever chemicals that take several years to break down and that accumulate in the body.

However, HFOs are not forever chemicals because they were purposely designed to break down. This was intentional to prevent HFOs from reaching the ozone layer and destroying it.

There has been concerns about secondary byproducts of the breakdown of HFOs, especially trifluoroacetic acid (TFA).

Choiniere quoted comments from the ozone secretariat of the UN Environment Programme (UNEP), which said that TFA concentrations are too low to pose a threat. Moreover, the biological effects of TFA are different from PFAS.

INTERNATIONAL APPROACH TO HFOS
States have defended their approach on PFAS definitions by pointing to steps being taken by regulators in Europe, Choiniere said.

However, the EU has not progressed to risk management, he said. Instead, the EU is reviewing any substances that have a CF2 or CF3 group, he said. That would include HFOs.

The UK PFAS Preliminary Regulatory Management Options Analysis is assessing the need for regulatory action.

In Canada, Environment and Climate Change Canada releases a report urging a class approach to PFAS using the definition of the Organisation for Economic Cooperation and Development (OECD).

While that definition encompasses HFO blowing agents, Canada’s current risk management recommendations only focus on firefighting foams, Choiniere said.

BANS AND FLUORINE CHEMISTRY
Broad definitions of PFAS could encompass materials beyond HFAS.

Fluoropolymers such as Chemours’s Nafion are used as membranes in hydrogen fuel cells and electrolysers, which split water molecules to produce green hydrogen with renewable energy.

Polyvinylidene fluoride (PVDF) is used as a lithium-ion binder and separator.

Fluoropolymers have dielectric properties that protect data from noise and preserve its fidelity in 5G networks.

Semiconductor fabrication plants, known as fabs, require tubing that can resist the chemicals used to etch wafers. Fluoropolymers are typically used because of their properties.

Choiniere said he was unable to comment about these restrictions spreading to other fluoromaterials because he is focused on fluorinated gases.

The Polyurethanes Technical Conference runs through Wednesday.

Polyurethanes are made with isocyanates and polyols.