The press on the EPA action is pretty bifurcated. Most are taking a victory lap, cheering that a producer of PFAS will cease production. A minority ask what will replace the technology slated for extinction. The nuances of this story make it interesting — and certainly create R&D opportunities.
Inhance has spent 40 years making plastic impermeable. They don’t make a special polymer and then use it to make impermeable items. They don’t make polymers. They take fully formed bottles and apply a treatment to make them impermeable. They don’t use PFAS in their manufacturing, they inadvertently make trace amounts. The treatment changes only a couple of microns of the surface yet reduces the diffusion of materials through the polymer. The bulk properties of the polymer are unchanged. A very little bit of fluorine goes a long way in reducing the permeability of polyolefin polymers.
Bottles that have sucked in are due to diffusion through the bottle. The term of art is “paneling.” Paneling occurs when the pressure inside a plastic bottle becomes less than the ambient air pressure outside, distorting the bottle. Stuff inside the bottle is escaping through the walls is one reason this occurs. Lots of the jugs and bottles we use are made from polyethylene and polypropylene. Both are excellent moisture barriers but poor gas barriers. Rates of diffusion of organic molecules can be high. The Inhance fluorination technology slows or stops this migration. The company boasts the flexibility and low cost that is hard to match.
Inhance adds fluorine and lets it react with the plastic surface. The company treats more than 200 million containers per year, and 25 million pounds of plastic packaging articles annually. Inhance states that fluorination makes “less than 15 grams of PFAS impurities.” The EPA uses a higher number. “The release of 2.2 Kg of these 9 PFAS could cause significant contamination of drinking water supplies leading to risks of adverse health effects in millions of people.” They aren’t clear on whether 2.2 kg represents their estimate of the level of contamination or not. Fortunately, others have looked at and reported in the peer-reviewed literature. A 2023 paper measures what is leached from treated polyethylene. They find 63.75 ± 13.2 ng/g plastic. That would be a little more than 700 grams in total for the 25 million pounds that Inhance says it treats. That is a couple of micrograms per container. For many materials, such low levels are permissible. They’re ignored.
There are a couple of things to unpack. The first is the ambiguous use of PFAS. The fluorinated polymer created contains multi-fluorinated carbon atoms. The polymer surface is a PFAS by all the currently operating definitions. Look at the average composition of the bottle and it isn’t. Most of the material is still just vanilla polymer. The EPA isn’t focused on the fluorine-containing polymer. The EPA is zeroing in on the inadvertent, slight production of certain perfluorinated acids, from C4 to C12 based on a recent EPA report. This includes the particularly well-studied and concerning PFOA. It is found in the bottles fluorinated by Inhance. The observation that drew attention to this issue was the leaching of PFOA from containers used for pesticides and the subsequent spraying of those pesticides creating PFOA contamination.
Whether a couple of micrograms per container is significant isn’t cut and dried. Inhance argues these are trace levels, sufficiently low enough to be ignored. Others, including the EPA, argue that, given the environmental persistence of the PFOA and other small molecule polyfluorinated substances, micrograms are too much. The EPA limits for PFOA are lower than other regulatory agencies. A recent review of legislation was forced to do a scale change to include the EPA levels on a plot. They are too small to see otherwise. Where PFAS levels become concerning is subjective. The low level set by the EPA is driving the targeting of Inhance.
The EPA, in this action, is focused on biproduct production. They’ve deemed producing PFOA or similar perfluorinated acids during processing violates TSCA. They aren’t, however, objecting to making fluorinated polymers. One stated advantage of Inhance’s technology is that the treated containers are fully recyclable with untreated polymer. The recycling symbol on a treated container is identical to an untreated one. The treated polymers and any coproduced PFAS will enter the recycling stream. That is concerning to some. Others point out that there are no degradation mechanisms that turn the polymers into smaller molecule PFAS. This is particularly pertinent because there are alternative fluorination technologies that do not produce the PFOA and similar materials produced in the Inhance process. In-mold fluorination is done in an oxygen and water-free environment where the production does not occur, just as one example. For now, the focus is only on the coproduct impurities. Processes for surface fluorination without coproducts are still okay.
We’ve all used fluorinated containers, most of the time without knowing it. Fluorination greatly reduces solvent permeation, reduces chemical attack, and can reduce or eliminate paneling, product loss, container discoloration, emitted odors, fragrance loss, flavor loss, and loss of active ingredients. It is incredibly useful for packaging personal care products, agrochemicals, automotive fluids, cleaning fluids, degreasers, essential oils, fuels, insecticides, lubricants, paints and paint thinner, solvents, and more. It is useful in making food containers, medical equipment, fuel components for automotive, and more.
If it goes away, we’ll need to replace it. R&D will be required.
Fluorination provides value and replacements must be found. Direct fluorination is almost magical. A tiny additive completely changes one trait of concern. Everything else stays the same. It would be great except that in most applications — though not all — human and environmental release of PFOA and PFOA-like materials occurs. Multilayer structures are a possibility for some applications. These generally aren’t recyclable. Designing non-fluorinated packaging and figuring out how to recycle it is a gaping need. It still may be that fluorination remains an option, with process improvements. It is disputed, but Inhance indicates it has made process improvements that address the issue. Others have demonstrated processes where problem compounds are undetectable. There is likely room for innovation. There is certainly a need for innovation.