European scientists have urged the European Commission to include a Mixture Assessment Factor (MAF) in the upcoming revision of the REACH Regulation. In a joint letter dated 26 May 2025, the academics warn that current single-substance assessments fail to reflect real-world chemical exposure, risking human health and the environment. This policy shift could significantly impact risk management strategies across manufacturing, chemicals, consumer goods, and other sectors.
Call for Action to Address Mixture Toxicity
REACH, the EU’s cornerstone regulation on chemical safety, currently evaluates substances in isolation. However, scientists from institutions including Stockholm University, RWTH Aachen, and Brunel University argue this model underestimates actual risk. They advocate for the implementation of a Mixture Assessment Factor—a pragmatic tool designed to account for the cumulative effects of multiple substances found in consumer products, food, and the environment.
According to the letter, the general European population is consistently exposed to chemical cocktails from various sources. Studies referenced include a 2024 Science article demonstrating neurotoxic effects in pregnant women from “safe-level” chemical mixtures, and EU human biomonitoring programmes showing pervasive contamination.
Widespread Support for Mixture Assessment Factor
The proposal has already gained support from the European Parliament, as well as national governments including Sweden, Denmark, Finland, and Luxembourg. The letter stresses that implementing the MAF would not significantly increase the regulatory burden on industry or authorities, referencing a detailed Swedish Chemicals Agency report.
“Scientific evidence overwhelmingly supports the need to shift from compound-by-compound to mixture-based risk assessments,” said Professor Christina Rudén, who coordinated the letter.
