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The US Environmental Protection Agency (EPA) wants to stop carrying out certain types of animal studies.
EPA Administrator Andrew Wheeler recently directed the agency he heads to reduce requests for, and funding of, studies that use mammals in toxicity testing by 30% by 2025. His goal is to eliminate all chemical toxicity testing in mammals by 2035.
In theory, this is a top-priority goal. The entire scientific community can be expected to unite in striving to reduce the use of animals in chemical toxicity testing, as long as it is scientifically possible.
However, we must have realistic expectations about the limits of the possible alternatives to animal studies. In some cases, there is no other way to assess the safety and efficacy of substances except by studying their effect on living organisms. There is no better example of this than biomedical research, the science that develops treatments that save and improve the lives of both people and animals.
Scientists are currently trying to develop computer models "strong" enough to simulate the equivalent animal studies well enough. But the technology required simply does not exist yet. Although experiments in cell cultures can indicate the effect of a substance or chemical at a basic level, they cannot simulate the many ways in which compounds affect complex living organisms, organisms with many interacting body systems.
For example, scientists cannot isolate the effect of a particular chemical on the immune system when a study is carried out only in cells, or even in whole organs. One possible scenario is a compound that causes an immune condition similar to lupus, which we would not be able to demonstrate in basic cell tests or in organs-on-chips.
Similarly, animal models are currently also the only way to determine whether chemicals will cause health problems at different stages of development: in the womb, in childhood and in adolescence.
"We do not yet have test systems that can mimic all the stages of human development," says Lee-Ann Burns Naas, former president of the American Society of Toxicology. According to her, "predicting the different effects on highly complex functions such as cognition, learning and memory is another challenge… Toxicologists are working feverishly on all these problems, but we cannot say with confidence that we will have solutions in the near future."
Intuitively, banning animal toxicity studies amounts to "opening the door" for toxic chemicals on their way to harming people.
Human studies are usually the last stage in determining a product's safety. Removing this intermediate stage could allow chemicals that may be toxic to humans to be approved for use, because scientists will not be able to prove their safety conclusively.
Alternative toxicity testing methods "could make it easier for the chemical industry to clear chemicals by saying they've done the required testing," said Kristi Pullen Fedinick, director of science and data at the Natural Resources Defense Council.
In addition, the EPA's decision carries the risk of opening the door to wider bans on animal studies in other fields as well, especially medical research. That would be disastrous for public health and for animal health too.
Look at the history of medical progress. It took decades of studies in monkeys, rats and mice to develop an effective polio vaccine. Research in chimpanzees helped develop an effective hepatitis B vaccine. Animal research is the reason we are able to perform organ transplants, heart bypass surgery, chemotherapy and blood transfusions.
Animals benefit from this research too. The vaccines given to pets, such as those against rabies, distemper, tetanus and feline leukemia, were all developed using animals as models.
More breakthroughs in this field are still to come. Animal studies are currently being carried out to develop new treatments for Alzheimer's, cancer, diabetes and countless other incurable diseases.
However, scientific progress is in danger of grinding to a halt if other agencies follow the EPA's lead and seek to restrict animal research. Although the effort may be well-intentioned, it could ultimately prove to be a costly mistake, putting at risk the long-term health, safety and well-being of the public, and even of their pets.