The US Environmental Protection Agency is reinstating its goal to eliminate mammalian animal testing by 2035, a policy shift that will accelerate the agency’s use of non-animal testing methods and reshape how regulatory laboratories support chemical safety decisions. The move restores a paused phase-out timeline and signals renewed federal pressure on labs to adopt validated alternative testing approaches.
For laboratories that conduct toxicity testing, generate regulatory data, or support chemical safety submissions, the announcement reopens a long-term regulatory transition that had slowed in recent years. The renewed direction places added emphasis on method selection, scientific validation, and operational readiness for non-animal testing strategies aligned with federal expectations.
EPA restores animal testing phase-out timeline
The EPA stated it is recommitting to the goal first established in 2019 to eliminate requests and funding for mammalian animal testing by 2035, including studies conducted by third parties. While some animal testing remains necessary to meet statutory requirements, the agency said it will further reduce vertebrate testing wherever scientifically and legally feasible.
The policy is being implemented through the EPA’s Office of Chemical Safety and Pollution Prevention, which oversees toxicity testing and chemical risk evaluations under the Toxic Substances Control Act. According to the agency, the office will prioritize high-quality alternative testing approaches that meet regulatory requirements while maintaining rigorous scientific standards.
EPA Administrator Lee Zeldin said the agency intends to advance alternatives to animal testing without delaying scientific progress, while continuing to meet legal obligations and data quality expectations.
Early indicators of operational change
The EPA cited recent actions as evidence that the animal testing phase-out is already affecting agency operations. In April 2025, the agency launched its first laboratory animal adoption program at its Research Triangle Park research facility, allowing staff to adopt animals no longer required for studies.
The agency also reported a sharp reduction in rodents housed by its Office of Applied Science and Environmental Solutions, with counts falling from 466 rodents in April 2025 to 41 by mid-November.
In regulatory science, the EPA’s Office of Pollution Prevention and Toxics applied non-animal testing approaches in cancer evaluations for dibutyl phthalate and di(2-ethylhexyl) phthalate. The agency estimates these evaluations avoided the use of approximately 1,600 mice and rats.
What New Approach Methods mean for regulatory laboratories
Central to the EPA animal testing phase-out is expanded use of New Approach Methods (NAMs). NAMs refer to technologies and methodologies used instead of vertebrate animal testing to inform chemical hazard identification and risk assessment.
NAMs include:
- In vitro assays using cell-based systems to evaluate toxicity pathways
- In chemico methods that assess chemical reactivity relevant to hazard identification
- In silico models that apply computational toxicology and predictive modeling
According to the EPA, NAMs can deliver faster, more reproducible, and more human-relevant data than some traditional animal studies. These methods also enable assessment of endpoints, life stages, disease states, and health outcomes that are difficult or impossible to replicate in laboratory animals.
Implications for lab managers and laboratory operations
For lab managers, the restored EPA animal testing phase-out reinforces the need to plan for greater reliance on non-animal testing strategies. Laboratories that support regulatory submissions or contract testing may need to reassess testing portfolios, instrumentation investments, and staff expertise.
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Operational considerations include validating NAM-based assays for regulatory acceptance, investing in analytical and computational tools, training staff in data interpretation and documentation, and tracking updated EPA guidance and waiver pathways under the Toxic Substances Control Act.
The EPA outlined a three-part strategy to support the transition, including identifying NAMs that can be used immediately, reviewing regulatory guidance to increase flexibility in meeting data requirements, and encouraging external researchers to apply for animal testing waivers.
As federal regulatory science continues shifting away from mammalian animal testing, laboratories that align early with NAM-focused workflows may be better positioned to meet evolving compliance expectations while maintaining data quality and operational continuity.
This article was created with the assistance of Generative AI and has undergone editorial review before publishing.
