Environmental Protection Agency (EPA)
The U.S. Environmental Protection Agency (EPA) is tasked with protecting human health and the environment through research, monitoring, standard-setting, and enforcement. Its Office of Chemical Safety and Pollution Prevention focuses on the risks posed by pesticides and toxic chemicals. The agency has historically relied on the results of animal tests to establish “acceptable” exposure levels for these chemicals, and millions of animals have been killed in these tests. However, in September 2019, the EPA announced that it will end its reliance on and funding of toxicity testing on mammals by 2035.
Science-Based Approach Will Reduce Animal Use and Better Protect Humans and the Environment
The EPA has taken steps to adopt the approach outlined in the landmark 2007 National Academy of Sciences report Toxicity Testing in the 21st Century: A Vision and a Strategy, which presents a strategy for moving away from animal testing toward cell-based and molecular approaches and the use of computational sciences. These non-animal methods allow thousands of chemicals and mixtures to be tested in a short period of time—which is not possible to do using animals. For example, in 2018, the EPA released a draft science policy on the use of non-animal approaches to skin allergy testing that have been shown to be equivalent or superior to animal tests in predicting human outcomes.
The EPA’s Office of Pesticide Programs (OPP) developed a “Strategic Vision for Adopting 21st Century Science Methodologies” that lays out the path and set of tools it will use to reduce its reliance on animal tests and make better-informed decisions regarding the hazards and risks of pesticide exposure. Significant progress has already been made. For example, EPA and PETA scientists coauthored a publication showing that a test on birds is not used to protect humans, and their analysis will be used to support waiving this test and thereby prevent hundreds of ducks and quails from being tested on each year. OPP is also involved in validating non-animal methods that can be used as replacements for tests in which pesticides are applied to the eyes and skin of rabbits in an attempt to assess eye and skin hazards. In another effort aimed at reducing animal use, OPP has analyzed years of pesticide data and determined that one of its required toxicity tests—for acute dermal toxicity—can be waived if certain criteria are met, sparing hundreds of animals each year. EPA has also developed guidance documents for waiving animal tests based on chemical properties and other factors. In addition, its ToxCast™ program applies high-throughput non-animal screening methods and computational toxicology approaches to rapidly prioritizing chemicals for further study and reducing the number of animals used. ToxCast has already been used successfully to reduce animal testing under the EPA’s Endocrine Disruptor Screening Program.
The passage of the Frank R. Lautenberg Chemical Safety for the 21st Century Act in May 2016 also contributed to the modernization of the EPA’s approach to evaluating chemical toxicity. This amendment to the outdated Toxic Substances Control Act requires that the agency develop, prioritize, and use non-animal testing methods before toxicity tests on animals are considered. The EPA published a strategy describing how it intends to carry out this mandate to develop and use alternative testing methods.
The results of animal tests are subject to interpretation and do not reliably predict what happens in humans. For example, if a chemical causes harmful effects in animal tests, researchers can claim that the results are not applicable to humans. An example is the herbicide atrazine, which has been repeatedly shown to cause negative health effects in tests on animals. Yet it remains on the market and in extremely widespread use because of claims that the effects seen in animals do not extend to humans, although mounting evidence is now suggesting otherwise.
At the same time, the results of animal tests have been used to suggest that certain toxic chemicals are safe for humans. This is what occurred with cigarettes for more than 20 years when tobacco was claimed to be safe for humans because animals who were forced to inhale cigarette smoke in laboratory experiments did not develop cancer. As a result of the inability of animal tests to reliably predict what happens in humans, products may be exempt from regulation for years while they are tested and retested on animals.
In contrast, in the late 1970s, huge doses of saccharin were shown to cause bladder cancer in rats, and products containing saccharin were required to be labeled with a cancer warning. Subsequent studies that examined how saccharin actually works in the body showed that the cancer results applied only to rats and, supported by human epidemiology studies that found no consistent link between saccharin and bladder cancer, the substance was removed from the government’s list of possible human carcinogens in 2000.