The US Environmental Protection Agency has adopted two approaches that reduce the need for animal studies in defined chemical and pesticide safety assessments. The methods address inhalation irritation caused by certain surfactants and acute oral toxicity from certain pesticide formulations.
The EPA announced the changes as part of its effort to expand the regulatory use of new approach methodologies, or NAMs. These methods include cell-based assays, computational models, and other tools that produce hazard information without testing on live vertebrate animals.
For laboratories conducting regulatory toxicology studies, the announcement moves two applications beyond broad policy support for NAMs and into defined assessment frameworks. However, the approaches apply to specified chemical classes and toxicity endpoints rather than serving as general replacements for animal testing.
Human tissue models support surfactant assessments
EPA’s New Chemicals Division has implemented an approach for evaluating the inhalation irritation potential of certain surfactants. Surfactants are found in products such as soaps, detergents, and cleaning formulations.
The framework combines information from three-dimensional human airway tissue with computational modeling. EPA has published an implementation memorandum, a structural classification guide, and data evaluations for two surfactants in its New Chemicals Division reference library.
The change gives laboratories and chemical developers greater clarity about the evidence EPA can use when reviewing applicable surfactants under the Toxic Substances Control Act. It also creates quality considerations for laboratories adopting three-dimensional tissue methods. Managers must consider tissue sourcing and qualification, acceptance criteria, assay controls, staff competency, culture conditions, and the reproducibility of results across runs.
Three-dimensional cell cultures can offer biological complexity that conventional two-dimensional cultures lack, but they can also require specialized handling and tighter control of experimental conditions. A regulatory application increases the importance of documenting those variables.
Ingredient data can replace some finished-mixture tests
For certain pesticide formulations, EPA will use the Globally Harmonized System mixtures equation to predict acute oral toxicity from information about the formulation’s known ingredients. The decision followed an analysis by the EPA and the National Institute of Environmental Health Sciences of nearly 700 pesticide formulations.
According to EPA, the analysis showed that the calculation could reliably identify formulations with low acute oral toxicity. In applicable cases, regulators can use the equation instead of requesting an animal study of the finished mixture.
For laboratories, this approach shifts part of the work from generating new in vivo data to managing existing ingredient data and calculation inputs. Managers supporting pesticide submissions should verify ingredient identities, concentrations, source records, calculation methods, and applicable limits before relying on the equation. Version control and documented review will also matter when computational outputs are included in a regulatory package.
Lab managers should confirm method applicability
EPA’s decisions add practical detail to a regulatory transition already underway. Earlier in 2026, the agency expanded its list of accepted NAMs, strengthening the role of alternative test methods in chemical safety assessments.
Laboratory leaders should not discontinue established animal protocols solely because EPA accepted these two approaches. Instead, they should determine whether their chemicals, formulations, endpoints, and regulatory pathways fall within the published frameworks. Early discussions with study sponsors and regulatory personnel can clarify which evidence EPA will accept.
Labs preparing to offer these methods should also assess equipment capacity, analyst training, method-transfer requirements, data systems, and quality-control procedures. EPA’s action creates an opportunity to expand non-animal testing capabilities, but regulatory acceptance still depends on using each approach within its defined scope and producing traceable, reviewable evidence.
This article was created with the assistance of Generative AI and has undergone editorial review before publishing.
