A new study by an Italy-based testing laboratory claims that a routine test for the presence of PFAS in textiles, designed to meet strict new regulations such as California AB 1817, is seriously flawed.
The problem is that the “non-target test,” which aims to measure the total organic fluoride content of an article, gives “false positives” if certain classes of reactive dyes are used to dye cotton fabrics.
The study was conducted by TIL in collaboration with the historic textile dyehouse Fratelli Ciampolini SpA in Prato to examine an important class of reactive dyes for cellulosic fibers that contain fluorine atoms in their molecular structure.
There are two types of laboratory tests used to detect the presence of PFAS in textiles and garments.
– “Target” testing: these methods focus on the determination of specific PFAS molecules (the “targets”), for which analytical standards are widely available. Unfortunately, however, to date, of the approximately 10,000 known PFAS molecules, only a few dozen standards and procedures are available that can be used for these “target” analyses.
– “Untargeted” screening analysis used to calculate the total fluorine (TF) and total organic fluorine (TOF) of an article. PFAS are fluorine-containing organic molecules, so technicians calculate their presence and subtract the TOF concentration value from the TF value to obtain a value that equals the amount of PFAS present in a sample.
The test assumes that all identified TOFs can be traced back to PFAS, which the researchers say is not true. Instead, the TIL researchers showed how some classes of reactive textile dyes that contain an organic fluorine molecule-and are not PFAS-are also sensitive to the test and thus give “false positives” when using this type of analytical method.
A textile article that does not contain PFAS would then be mistakenly flagged by authorities as something to be banned, or at least subject to the same chemical restrictions as PFAS.
However, the fluorine-containing reactive dyes in question are not the same persistent organofluorinated compounds that the regulators rightly intend to restrict, the researchers say.
“La presenza dell’atomo di fluoro (organico) nella molecola di questi coloranti non li classifica in alcun modo come sostanze PFAS”, si legge nel rapporto. Il rapporto sottolinea inoltre che: “Le sostanze per e polifluoroalchiliche (PFAS) sono definite come qualsiasi sostanza che contenga almeno un atomo di carbonio metilico (CF3-) o metilenico (-CF2-) completamente fluorurato (senza H/Cl/Br/I ad esso collegato)”.
This is important because new PFAS regulations are being implemented globally. The state of California, for example, has set restrictions on PFASs by imposing a limit of 100 mg/kg total organ fluoride (TOF) as of January 2025 and will tighten it to 50 mg/kg as of January 2027.
“Europe also seems to be going in the same direction, in fact, in addition to the existing specific restrictions for some PFAS molecules (‘target’ criterion), a proposal for a general restriction of PFAS, based on the ‘untarget’ criterion, is being worked on, following which a proposal for a 50 mg/kg limit for TOF is being studied,” the Italian researchers said.
Ecotextile News contributor Phil Patterson noted, “I would agree with the Italian researchers’ definition of PFAS, but the California authorities do not: they say that any molecule with a fully fluorinated carbon atom, such as these dyes, is a PFAS.
“It is clear that these dyes are not persistent organics. By fixing them on a cellulosic substrate or showing them some water and/or alkali, they readily decompose releasing inorganic HF.”