The US Environmental Protection Agency has adopted two nonanimal methods to assess the toxicity of surfactants and pesticides in its latest move away from animal testing, the agency announced in an Aug. 27 press release.
“EPA is leading the way on eliminating animal testing by embracing cutting-edge, gold standard science like never before,” EPA administrator Lee Zeldin says in the press release. “With these new scientific advancements, we are fostering American innovation and raising the bar when it comes to the research methods used when evaluating new chemicals and pesticides.”
But while animal welfare advocates support the development, one scientist warns that the new methods have limitations and shouldn’t be used to completely replace animal models.
During President Donald J. Trump’s first term, the EPA announced plans to stop conducting and funding chemical safety testing on animals (PDF) by 2035. The agency scrapped that plan under the Joe Biden administration due to concerns over feasibility, but Zeldin reinstated it in January.
As part of the plan, the EPA is actively pursuing new approach methodologies like computer modeling and equation estimates that predict chemical toxicity without the use of animal models. The European Union announced in June similar plans to move away from animal testing for chemical safety assessments. The EPA’s Aug. 27 announcement includes a cell model derived from human airway cells to predict the lung irritability of surfactants and a mixtures equation to predict the oral toxicity of some pesticides.
Animal protection group Humane World Action Fund and PETA Science Consortium International, which advocates for nonanimal methodology in research, both support the EPA’s adoption of the new methods, according to the EPA press release. “These are exactly the types of specific, science-based documents that will encourage broader industry use of reliable and relevant non-animal approaches,” Amy J. Clippinger, president of PETA Science Consortium International, says in the release. PETA Science Consortium International collaborated with the EPA to develop the surfactant cell model.
But Jennifer Sass, a senior scientist at the Natural Resources Defense Council (NRDC) who specializes in toxic chemical regulation, tells C&EN that the EPA is overselling the benefits of the cell model and mixtures equation.
The surfactant model is difficult to reproduce, Sass says, since it relies on immortalized cells derived from human cells that grow and mutate like cancer. “Their variability is high, their reproducibility is low across labs,” she says. “Then, in order to scale these up, they require a huge amount of robotics, and nothing is cheap.”
Sass also questions the utility of the pesticide mixtures equation. An EPA research paper on the mixtures equation showed that 55% of the equation’s results aligned with previous in vivo animal model results and that the equation was more likely to underestimate risk.
“It was roughly a flip of a coin whether it was going to find a high toxicity,” Sass says. The authors also wrote that the equation is helpful in predicting low toxicity of mixtures. “So it didn’t work for really toxic mixtures,” Sass says. Her concern is that the EPA will override past rodent data and epidemiology and rely instead solely on this equation to predict pesticide risk.
Sass adds that while these new models are tools in the toolbox of chemical toxicity assessments, they shouldn’t completely replace animal models. “I hope we continue to develop them; I think they’re important,” Sass says. “But I think we need to have a lot more humility and a lot more public engagement, and this announcement is the opposite.”
The EPA did not respond to a request for comment by publication time.
