On December 20, 2016, the U.S. Environmental Protection Agency (EPA) announced the start of a pilot program to evaluate the usefulness and acceptability of a mathematical tool (the GHS Mixtures Equation), which is used in the Globally Harmonized System of Classification and Labeling of Chemicals (GHS). EPA states that the goal of the pilot program is to “evaluate the utility and acceptability of the GHS Mixtures Equation as an alternative to animal oral and inhalation toxicity studies for pesticide formulations.”

For this pilot program, EPA is requesting submission of acute oral and acute inhalation toxicity study data paired with mathematical calculations (GHS Mixtures Equation data) to support the evaluation of pesticide product formulations; instruction for doing so are available on the GHS Equation Pilot Program webpage, and Guidance on the GHS Mixtures Equation is available in the Guidance on the Application of the CLP (Classification, Labeling and Packaging) Criteria.

The program is an interesting approach considering the conceptual differences of risk assessment and hazard determination that exist at the core of EPA risk approaches and GHS fundamentals. Also, the definition of the EPA Categories compared to GHS has been problematic for hazard communication applications.

Mixture calculation tools rely on the availability of data for all components and would only be applicable if the data for each were generated using the same species under similar exposure conditions.

This pilot program is being developed under EPA’s initiative to develop non-animal alternatives for acute toxicity testing, as well as EPA’s Office of Pesticide Programs’ Strategic Vision for Adopting 21st Century Science Methodologies. More information on these initiatives can be found on our Pesticide Law and Policy blog under key phrase “toxicity testing.”