National Toxicology Program

“The problem is we don’t know what the findings really mean.”
—Dr. Robert Maronpot, former chief of the National Institute of Environmental Health Sciences’ Laboratory of Experimental Pathology

For more than 30 years, the U.S. National Toxicology Program (NTP) has been using your tax dollars to poison small animals with massive doses of pesticides, drugs, and other chemicals to see if the animals develop cancer.

Beginning even before they are born and continuing every day for up to two years, rats and mice are forced to consume food or water laced with a test chemical, have the substance pumped down their throats and into their stomachs, or are stuffed into inhalation-chamber restraint tubes and forced to inhale the test chemical as a vapor.

And as if that weren’t enough, the doses that animals are given are often so high that they cause sickness and suffering over and above that caused by tumor growth and disease. Perhaps not surprisingly, the NTP reports that as many as 70 percent of animals may not even survive to the end of a two-year cancer study.

Just one of these studies takes approximately five years to design, conduct, and interpret; kills as many as 860 animals; and costs up to $4 million. Yet despite this enormous cost to animals and American taxpayers, the former chief of the NTP’s experimental pathology laboratory has admitted,
“[W]e don’t know what the findings really mean.”

“Even if a chemical is found to be nontoxic in animal studies, the safety of the chemical cannot be assured.”
—Dr. Barbara Shane, former NTP executive secretary

PETA conducted its own analysis of the NTP’s rodent cancer testing program, the complete results of which are published in our report “Wasted Money, Wasted Lives: A Layperson’s Guide to the Problems With Rodent Cancer Studies and the National Toxicology Program.” Based on our review of all 502 federally funded and conducted lifetime rodent cancer studies published on the NTP website as of January 2006 as well as more than 25 years of published scientific literature on this subject, we have determined that much of the U.S. government’s more than $1 billion investment in the NTP rodent cancer testing program has been a waste. The funding has been used to underwrite studies that have been found to have some or all of the following characteristics:

  • They have been judged to be utterly “inadequate” or to produce “equivocal” (ambiguous) results, which are of no use to health authorities.
  • They produce such dubious and conflicting results that more than 75 percent of NTP-tested chemicals are not even classified according to their cancer risk to humans or are lumped into such meaningless categories as “possible” human carcinogens or “unclassifiable” as to human cancer risk—designations that do nothing to enhance public health or worker protection.
  • They have been shown by other scientists to produce consistent and reproducible results only 57 percent of the time when the same chemicals are tested repeatedly using the same method.

History also reveals that critical public-health and worker-protection measures related to cigarette smoke, asbestos, benzene, and other cancer-causing substances were delayed for many years because of misplaced trust in animal tests, which could not easily replicate cancerous effects that had already been documented in people. If standard animal tests failed to readily identify these well-known human carcinogens, how many other dangerous chemicals are Americans exposed to today as a result of misleading animal data?

Animal Testing for Chemicals Already Considered Safe

The NTP actively encourages people to nominate (even anonymously) chemicals that they would like to see tested on animals. This has led to a long list of ill-conceived NTP testing recommendations, including proposals to conduct extensive animal testing of substances that have been used without harm for many years.

Dietary Supplements and Herbal Medicines

The NTP conducts cancer tests and other animal tests on dietary supplements and herbal medicines that have a long history of safe use in traditional medicines with few reported incidences of harmful effects. In November 2009, PETA commented on the NTP’s plans to conduct testing for butterbur, evening primrose oil, and valerian, urging the NTP to thoroughly consider human experience, existing toxicity data, and the application of non-animal test methods in order to avoid unnecessary and duplicative animal tests. PETA also commented on the NTP’s proposed testing for dong quai, a Chinese herbal remedy used for thousands of years primarily to treat conditions of the female reproductive system. PETA reminded the NTP that dong quai had already been recognized as safe by the U.S. Food and Drug Administration and had undergone massive animal testing, making it difficult to understand why the NTP was calling for even more testing in some of these areas.

The NTP continues to conduct and/or call for animal testing of popular dietary supplements and herbal medicines such as ginseng, echinacea, aloe vera, and green tea. The NTP generally discounts the wealth of human experience indicating that these products are safe, focusing instead on one or two laboratory studies reporting questionable results. Animal testing of dietary supplements and herbal medicines by the NTP should be suspended, and these substances should be reevaluated on a weight-of-evidence basis, giving due consideration to existing human experience.

Soy Infant Formula

In March 2010, PETA commented on the NTP’s recommendation of extensive animal tests for soy infant formula. Although soy-based formulas have been used safely since the early 1960s to feed more than 20 million infants, the NTP called for numerous new animal studies that were clearly not applicable to humans. Some of the NTP’s recommended studies included giving rodents an isolated chemical of soy infant formula, rather than the entire chemical mixture, in doses far in excess of human exposures via dissimilar exposure routes. In addition, rodents have a completely different metabolic profile for soy isoflavones than do humans. Although several members of the NTP’s advisory board agreed with PETA’s comments, the NTP’s recommendations remained unchanged.

Asbestos and Artificial Butter Flavoring

In May 2006, PETA commented on the NTP’s recommended inhalation toxicity tests of asbestos and artificial butter flavoring in rodents. It has been clearly demonstrated that inhalation results in rodents don’t apply to humans because of physiological differences between species, and the additional animal tests only serve to further delay the implementation of measures to protect people from these known dangerous substances.

The NTP Advisory Board Sides With PETA on Some Chemicals

While PETA scientists regularly comment on chemicals that are nominated for study to the NTP, in a number of cases, the NTP Board of Scientific Counselors (BSC) has agreed with PETA and recommended a low priority for animal tests. Following PETA’s comments at a December 2010 meeting, for example, the BSC’s review of an extensive animal testing program proposed for chemical mixtures was highly critical, citing a number of points made by PETA. A thoughtless approach in this active area of research could lead to an unlimited increase in the numbers of animals used in toxicity testing since already-characterized substances could be retested in endless combinations. Fortunately, it seems clear that this plan is now headed back to the drawing board. At the same meeting, the BSC agreed with PETA’s comment on a proposal for more animal tests on flame retardants that NTP scientists had neglected to mention 70 years’ worth of existing research on one of the substances that had been selected for even more in-depth animal testing.

Within the past few years, a chemical used in sunscreens and cosmetics (2-ethylhexyl p-methoxycinnamate) was nominated for carcinogenicity and multi-generation reproduction toxicity tests, and the BSC agreed with PETA that the material supporting its nomination was out of date, noting that a quick literature search found dozens of relevant publications that had not been considered. Finally, the BSC recommended that multi-generation reproduction toxicity experiments on a plasticizer used in consumer products (diethyl phthalate) should be put on hold after PETA questioned the relevance of previously conducted animal experiments to humans.

Click here to learn more about PETA’s petitions to stop the NTP’s endless proposals for animal testing.

Click here to learn about the Interagency Coordinating Committee on the Validation of Alternative Methods, which is overseen by the NTP and whose task it is to promote non-animal test methods for government-required testing.

How You Can Help

Your congressional representatives need to hear that you don’t want any more of your tax dollars used to underwrite the NTP’s rodent cancer testing program and animal tests for substances, such as dietary and herbal supplements, that have long been considered to be safe. Respectfully urge them to divert public money from cruel animal experiments into promising, lifesaving, and relevant clinical and non-animal research.

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 Ingrid E. Newkirk

“Almost all of us grew up eating meat, wearing leather, and going to circuses and zoos. We never considered the impact of these actions on the animals involved. For whatever reason, you are now asking the question: Why should animals have rights?” READ MORE

— Ingrid E. Newkirk, PETA President and co-author of Animalkind