Tom Neltner, Chemicals Policy Director, Maricel Maffini, consultant, and Tom Bruton with Green Science Policy Institute.
Results from an Environmental Protection Agency (EPA) investigation into PFAS-contaminated pesticides have much broader, concerning implications for food, cosmetics, shampoos, household cleaning products, and other consumer products, as well as recycling. This investigation, first announced earlier this year, found that fluorinated high-density polyethylene (HDPE) containers used for pesticide storage contained a mix of short and long-chain per- and polyfluorinated alkyl substances (PFAS), including PFOA, that leached into the product. From what EPA can tell, the PFAS were not intentionally added to the HDPE containers but are hypothesized to have been produced when fluorine gas was applied to the plastic.
Since EPA released its investigation, we have learned the disturbing fact that the fluorination of plastic is commonly used to treat hundreds of millions of polyethylene and polypropylene containers each year ranging from packaged food and consumer products that individuals buy to larger containers used by retailers such as restaurants to even larger drums used by manufacturers to store and transport fluids.
The process of polyethylene fluorination was approved by the Food and Drug Administration (FDA) in 1983 for food packaging to reduce oxygen and moisture migration through the plastic that would cause foods to spoil. The fluorination process forms a barrier on the plastic’s surface and it also strengthens the packaging.
Fluorination of plastic leading to the inadvertent creation of PFAS may be another reason these ‘forever chemicals’ show up in many unexpected places. This significant source of PFAS contamination needs to be addressed. Much remains to be resolved as FDA and EPA actively investigate this new source of PFAS; however, preventive steps need to be taken quickly, especially since other PFAS-free barrier materials are available as alternatives.
Growing evidence links PFAS to a wide range of serious health effects – from developmental problems to cancer.
FDA’s approval of fluorine gas treatment of polyethylene
FDA rules, promulgated in 1983, allow the use of fluorine gas to treat polyethylene food-contact articles in amounts that produce up to 5,000 parts per billion (ppb) of total fluorine in the food in the container. The rule states that the process affects only the surface of the polyethylene and leaves the interior of the plastic unchanged.
In practice, the fluorine gas substitutes the hydrogen molecules on the plastic’s surface with fluorine, effectively creating a barrier to moisture and oxygen migration through the polyethylene. The newly created barrier also makes the plastic stronger by preventing the contents from penetrating the plastic and making it softer. We submitted a Freedom of Information Act (FOIA) request to FDA in May to obtain the documents surrounding FDA’s 1983 approval and the basis of its determination that the use was safe. We will share more information when we get the agency’s response.
The 5,000 ppb level of total fluorine in a container’s food translates into extremely high levels of PFAS exposure for consumers. Using PFOA as an example, this limit would allow up to 7,260 ppb of PFOA in the food. To provide context, consider a one-liter bottle of fluorinated HDPE where only 1% of the PFAS made from the fluorination process was PFOA; an adult consuming the one-liter of beverage each day would be exposed to more than 300 times the Minimal Risk Level that FDA, EPA, and Centers for Disease Control and Prevention have established for intermediate-duration exposures. And this wouldn’t include the risks from other types of PFAS also generated during fluorination or exposures to the substances from other sources.
We have been told by packaging experts and found in marketing materials that fluorination is also used on polypropylene, but we cannot find any FDA approval for the use. If this is happening without an FDA authorization, food manufacturers could be self-certifying the use of fluorine gas as Generally Recognized as Safe (GRAS) without FDA review, a practice that FDA allows and that EDF and Center for Food Safety have challenged in court.
EPA identified eight PFAS from HDPE containers for mosquito control pesticide
In its investigation into the PFAS-contaminated pesticides, EPA suspected the fluorinated HDPE containers as a potential source of the contamination and tested various sizes of used and unused fluorinated and non-fluorinated containers that was representative of the supply chain for pesticides (see photos below). In March 2021, EPA released final results of its investigation, and confirmed that the fluorination process is what produced the PFAS.
EPA rinsed eight HDPE containers for a very short time – only a minute – at room temperature with a small amount of methanol. Then it tested the rinsate for PFAS and positively identified eight PFAS with carbon-chain lengths between three and ten fully fluorinated carbons, including PFOA. The total level of the PFAS found ranged from 20-50 ppb in four unused containers; two used containers had lower, but still significant levels.
In contrast, the non-fluorinated containers had 1 ppb or less. See Figure 1 below from the EPA report for more detail. During this extremely short contact at room temperature, between 1 and 17 micrograms (µg) were extracted in the rinsate. If the contact time were longer and temperature was hotter to more closely represented actual conditions of storage and transport, the amount extracted would almost certainly have been greater.
In its conclusion, the agency stated that it “believes that through the fluorination process of HDPE containers, PFAS compounds may be formed and then partly leach into the products inside the containers.” EPA further explained that:
- During the fluorination process, HDPE containers are subjected to fluorine elemental gas at pre-determined concentrations and under elevated temperatures; and
- The length of time and the conditions under which the product is stored in the fluorinated containers could affect the leaching potential, and consequently the concentration of PFAS found in the products.
EPA also indicated that in future studies it will test these materials under a variety of different conditions including other solvents, different contact times and temperatures and different product storage time to better understand what impact fluorination has on plastic containers and their contents.