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Table of Contents | Introduction |  What are PFAS?  |  PFAS Regulations  |  PFAS in Semiconductor Mfg  |  Components with PFAS  |  Actions 

On this page you will find:

  • PFAS Concentrations of Regulatory Interest
  • PFAS Regulatory Definitions
  • SEMI PFAS Definition
  • A Listing of PFAS
  • PFAS Fluoropolymer Names

PFAS Concentrations of Regulatory Interest

In the above regulations, the concentration of regulatory interest (CRI) varies from complete bans on PFAS (i.e., no intentionally added concentration of PFAS is allowed) to concentrations on the order of 25 parts per billion (0.0000025%) for a single PFAS substance or several hundred parts per billion (ppb) for the sum of all PFAS substances.

As an example, the broad spectrum European PFAS restriction being proposed for the REACH regulation has a base restriction as follows for an substance, mixture, or article:

  • “i. 25 ppb for any PFAS as measured with targeted PFAS analysis (polymeric PFASs excluded from quantification)
  • ii. 250 ppb for the sum of PFASs measured as sum of targeted PFAS analysis, optionally with prior degradation of precursors (polymeric PFASs excluded from quantification)
  • iii. 50 ppm for PFASs (polymeric PFASs included). If total fluorine exceeds 50 mg F/kg the manufacturer, importer or downstream user shall upon request provide to the enforcement authorities a proof for the fluorine measured as content of either PFASs or non-PFASs.”

In consideration of concentrations, it important to note that the denominator of the concentration can also vary. In Europe, regulations applicable to components usually are for “articles” which, in accordance with the 2015 “once and article always an article” interpretation of the European Court of Justice, roughly means any individual part of the component that has ever existed separately in commerce – a simple potentiometer can be composed of 20 or so individual articles. In the United States the EPA uses the term “article” to mean the item as it is placed on the market – the same potentiometer would be considered as one single article. 

{water regulations have an interest level much lower}

PFAS Regulatory Definitions

Unfortunately, all these regulations do not share a common definition for PFAS, although there are trends appearing in definitions as well. A few of the more noteworthy definitions are shown here. Note that within the same jurisdiction (and even within the same jurisdiction agency) the definitions are not always the same.

Definition Source

Definition

Proposed EU REACH general PFAS restriction.

Any substance that contains at least one fully fluorinated methyl (CF3-) or methylene (-CF2-) carbon atom (without any H/Cl/Br/I attached to it).

 

[The definition has this further scope qualification – it is not clear if it is legally considered part of the PFAS definition or not.]

A substance that only contains the following structural elements is excluded from the scope of the restriction:

CF3-X or X-CF2-X’, where X = -OR or -NRR’ and X’ = methyl (-CH3), methylene (-CH2-), an aromatic group, a carbonyl group (-C(O)-), -OR’’, -SR’’ or –NR’’R’’’; and  where  R/R’/R’’/R’’’  is a hydrogen (-H), methyl (-CH3), methylene (-CH2-), an aromatic group or  a  carbonyl  group(-C(O)-).

Proposed EU REACH restriction for PFAS in firefighting foams

Any substance that contains at least one fully fluorinated methyl (CF3) or methylene (CF2) carbon atom (without any H/Cl/Br/I attached to it).

EPA proposed PFAS reporting rule.

Any chemical substance or mixture that structurally contains the unit R-(CF2)-C(F)(R′)R″. Both the CF2 and CF moieties are saturated carbons. None of the R groups (R, R′ or R″) can be hydrogen.

EPA proposed SNUR for inactive chemicals.

(i) R-(CF2)-CF(R′)R″, where both the CF2 and CF moieties are saturated carbons;

(ii) R-CF2OCF2-R′, where R and R′ can either be F, O, or saturated carbons; and

(iii) CF3C(CF3)R′R″, where R′ and R″ can either be F or saturated carbons.

State of Maine PFAS reporting and restriction statute

Substances that include any member of the class of fluorinated organic chemicals containing at least one fully fluorinated carbon atom.

New York state proposed PFAS reporting and restriction statute

Substances that include any member of the class of  fluorinated  organic chemicals containing at least one fully flourished [sic] carbon atom.

Some PFAS regulations have a scope limited to specific list of PFAS substances, such as the US Toxic Substances Control Act (TSCA) Significant New Use Rule (SNUR) for Long-Chain Perfluoroalkyl Carboxylate and Perfluoroalkyl Sulfonate Chemical Substances (LCPFAC) at 40CFR721.10536.

The SEMI PFAS Definition

As members of SEMI in collaboration with the Semiconductor Industry Association strive to identify PFAS being used in the semiconductor industry, we are using a fairly broad definition of PFAS:

All chemistries and materials that contain molecules with -CF2- and/or -CF3

A Listing of PFAS

There is no single list of PFAS in accordance with this definition. However, the United States EPA has a “list of lists” of PFAS available at https://comptox.epa.gov/dashboard/chemical-lists/PFASMASTER. Some PFAS are listed on more than one of the 10 lists shown there. In total, there are more than 12,000 unique substances among the lists. It is not clear which PFAS definition the EPA uses for their lists, but it is likely to be narrower that the PFAS definition used by SEMI and by most US states.

PFAS Fluoropolymers Names

As mentioned above, fluoropolymers are PFAS. Fluoroelastomers are also PFAS. When researching the use of PFAS in components, a manufacturer might find that the material specification block of their drawings indicates a fluoropolymer trade name rather than the generic name. For example, it might indicate, “Teflon” or “Efalon” rather than PTFE or “15% Glass Filled PTFE”.  Therefore, it is important to be familiar with the trade names of fluoropolymers and fluoroelastomers as well as their generic names. 

The following are several generic fluoropolymer and fluoroelstomer names, followed by some trade names.

Common fluoropolymers and fluoroelastomers – Generic Names

(all are PFAS)

Molecular Structure Models

--- Fluoropolymers ---

Acronym

Name

CAS number

Formula

Index

ECTFE

Ethylene Chloro Tri Fluoro Ethylene

25101-45-5

(CF2-CFCl-C2H4)n

A

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ETFE

Ethylene Tetra Fluoro Ethylene

25038-71-5

(C2H4-C2F4)n

B

FEP

Fluorinated Ethylene Propylene

25067-11-2

((C2F4)n + (C2F3-CF3)m)

C

PCTFE

Poly ChloroTri Fluoro Ethylene

9002-83-9

(C2F3-Cl)n

D

PFA

Per Fluoroalkoxy Alkane

26655-00-5

((C2F4)n + (C2F3-(O-CF3)m)

E

PTFCE

See PCTFE

PTFE

Poly Tetra Fluoro Ethylene

9002-84-0

 (C2F4)n

F

PVDF

Poly Vinyl iDene Fluoride

24937-79-9

(CH2-CF2)n

G

PVF

Polyvinyl fluoride

24981-14-4

(C2H3F)n

H

--- Fluoroelastomers ---

 

FKM
  • Fluoroelastomers do not have specific CAS numbers nor definite molecular structures.
  • ‘FKM’ and ‘FFKM’ are not acronyms, they are material designations from the ASTM D1418 standard. They are also classified in ISO/DIN 1629 as ‘FPM’ and ‘FFPM’. FKM / FPM are ‘fluoroelastomers’ and FFKM / FFPM are ‘perfluoroelastomers’.
  • FKMs are made from a mixture of 6 monomers (VF – vinylidenefluoride, HFP – hexafluoropropylene  TFE – tetrafluoroethylene, PMVE – pefluoro methyl-based vinyl ether, E – ethylene, P – propylene) and two main ‘curing’ systems which result in 5 types of FKMs.
  • FFKMs are basically made from two monomers and an additional ‘cure site monomer.’

FFKM

FPM

FFPM

The following list of trade names also demonstrates that the inventor of a particular fluoropolymer product might license out the manufacture and/or sale of the product to another company. 

You can also see that some of trade names represent very large families of fluoropolymers of types, sometimes with many sub-grades in the family.

Read More about Trade Names, PFAS Additives & Non-PFAS Polymers

Please note:  SEMI makes no warranties or representation to the accuracy or usefulness of the information contained on this webpage. Accuracy is solely the responsibility of the user.  Users are cautioned to refer to other relevant literature of the subject matter herein.  This information is subject to change without notice. This "explainer" was developed by members of the SEMI PFAS Working Group. Please send suggestions for improvement to [email protected]