The European Food Safety Authority (EFSA) has proposed updated consumer health-based guidance values for trifluoroacetic acid (TFA), citing new evidence from toxicological and human studies. A public consultation is open until 22 September 2025, allowing stakeholders across the chemicals and manufacturing sectors to contribute feedback before final values are confirmed.
Revised ADI and ARfD Values Reflect New Evidence
At the request of the European Commission, EFSA's Pesticide Peer Review Unit re-evaluated the acceptable daily intake (ADI) and introduced, for the first time, an acute reference dose (ARfD) for TFA. The new values are:
- ADI: 0.03 mg/kg body weight per day
- ARfD: 0.6 mg/kg body weight
(Both expressed as sodium trifluoroacetate)
These values were derived using a weight-of-evidence (WoE) approach, incorporating 170 studies, including developmental and reproductive toxicity data, biomonitoring, and mechanistic studies. A significant driver for the revised ADI was a reduction in thyroid hormone levels observed in an extended one-generation reproductive toxicity study in rats.
Trifluoroacetic Acid: Widespread Use and Exposure
TFA is a persistent degradation product of various industrial chemicals including refrigerants, fluorinated polymers, and pharmaceuticals. It is also a known metabolite of several PFAS and pesticide active substances, which has raised concern over cumulative and long-term human exposure.
Human biomonitoring studies confirm widespread exposure. One study in adults reported TFA serum concentrations with a 97% detection rate (median: 8.46 ng/mL). Notably, TFA was also detected in umbilical cord serum, providing evidence of foetal exposure during pregnancy.
Mechanistic and Health Risk Insights
EFSA concluded that TFA is not genotoxic, based on a comprehensive battery of in vitro and in silico studies. However, evidence of developmental toxicity in rabbits (including ocular malformations) led to the introduction of the ARfD at 0.6 mg/kg bw.
Although no carcinogenicity studies were available, EFSA applied additional uncertainty factors due to data gaps. These included the absence of a long-term carcinogenicity study and the lack of functional immunotoxicity tests.
