New US EPA documents released on use of the GHS Mixtures Equation for predicting acute oral toxicity of pesticide formulations and use of human cell–based methods for assessing respiratory effects of surfactants

Today, the US Environmental Protection Agency (EPA) released two sets of documents advancing the use of reliable non-animal approaches.

The EPA Office of Pesticide Programs (OPP) released a new document providing guidance on the use of the United Nations Globally Harmonised System for Classification and Labelling (GHS) Mixtures Equation in place of certain acute oral toxicity tests for pesticide products. This calculation-based approach can be used to predict the toxicity of a mixture based on the toxicity of each of its ingredients and is widely used around the world, including in the United Kingdom and European Union.

The document follows an EPA-organised pilot program where pesticide registrants submitted paired data from in vivo acute toxicity testing in rats alongside results from the GHS Mixtures Equation. The EPA then partnered with the National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) to analyse the data and publish the findings. The Science Consortium is co-hosting a webinar on this topic later this year (to be announced here).

Read the EPA’s GHS Mixtures Equation document here.

Additionally, the EPA Office of Pollution Prevention and Toxics (OPPT) released new documents providing guidance on respiratory irritation testing of surfactants. The agency notes that the EPA is using in vitro data from human cell–based tissue models for human-relevant decision-making, emphasises that data from human cell–based models will be prioritised over animal tests, and highlights further collaborative research ongoing at the EPA’s Office of Mission Control Operations (OMCO) to generate additional surfactant data that will help inform decision-making. The guidance references four publications co-authored by EPA, the Science Consortium, and others that support the approach.

Read the EPA’s documents on respiratory effects of surfactants here.

These documents come on the heels of other EPA documents that clarify testing requirements, such as OPPT documents on how to consistently and transparently assess eye and skin irritation testing with a preference for the use of human cell-based methods, and an updated “List of NAMs” to help stakeholders identify reliable non-animal testing approaches.