Animals in Science / Education

The Environment and Dissection

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Disposal of Toxic Waste

Toxic chemicals such as formaldehyde or formalin (a diluted form of formaldehyde) preserve millions of animals each year. Formaldehyde is “known to be a human carcinogen,” 1 and is also considered a hazardous air and water pollutant and waste material by the Environmental Protection Agency; municipalities and industry have detected formaldehyde in their drinking water, rainwater, lake water, and other waterways. Exposure to Formaldehyde, which can occur through inhalation or absorption through the skin from products containing the chemical, can cause extreme irritation and severe allergic reactions of the skin, eyes, nose, throat, and respiratory system. Unsurprisingly, people with a potentially high risk of exposure include “teachers and students who handle biological specimens preserved with formaldehyde or formalin.”2

While other substitutes for formaldehyde do exist, they have not been on the market long enough to truly determine safety and still often contain formaldehyde as a key ingredient. These substitutes also do not necessarily preserve specimens in an acceptable form for dissection. Overall, the disposal of specimens by thousands of classrooms every year presents a risk not only to the individual teacher and students involved, but also to the environment and subsequently public health. Frogs, for instance, are excellent indicators of environmental changes and the number of amphibian malformations documented in at least 60 species throughout the U.S.3 is a cause of concern, not only for the animals, but for human health as well. Past studies have documented that not all schools follow strict environmental guidelines for disposing the hazardous waste of dissected animals’ remains.

Depletion of Organisms from Natural Habitats

The exact number of animals killed and preserved for dissection labs each year is unknown. However, millions of vertebrate animals are used annually in high school dissection classes alone. Amphibians, reptiles, fish, birds, and most invertebrates are among the many species who are collected from natural habitats each year for dissection purposes. Frogs are the most commonly dissected animal in elementary and secondary school, and they are often wild-caught. One of the largest suppliers, the Carolina Biological Supply Company (CBSC), claims that it “obtains animals from many sources – some from cultures, some from natural or managed habitats where seasonal collections are made, and many from the food industry.” As with many biological supply companies, CBSC does not state specifically the origin of all its amphibians, but does admit to wild-harvesting. A 2003 survey of 14 supply companies found that only one company exclusively used farm raised amphibians.4

Amphibian populations throughout the world are in peril; nearly one-third of all known amphibian species face extinction.5 Even in areas largely protected from habitat destruction and chemical pollution, like Yosemite National Park in CA, frog species are disappearing. In the U.S., at least “56 amphibians, or about 20.5 percent, are at risk of dying out,” according to the Center for Biological Diversity. In addition to contributing to the already rapid depletion of frog populations worldwide, the harvesting of frogs from the wild also upsets the balance of local ecosystems (e.g. pest control), while captive-bred, non-native frogs create infectious disease risks and invasive species concerns for fragile, native populations. A 2012 survey of nearly 2,000 teachers in the U.S. and Canada found that “one out of four educators who used live [non-native] animals as part of their science curriculum released the organisms into the wild after they were done using them in the classroom.”6


  1. National Toxicology Program. (2011). Report on Carcinogens, 12th Edition.
  2. Occupational Safety and Health Administration. (2011). Formaldehyde Fact Sheet.
  3. AmphibiaWeb. (2003, September 23). Overexploitation. AmphibiaWeb: Information on amphibian biology and conservation. Berkeley, CA, University of California.
  4. Jensen, J. B., & Camp, C. D. (2003). Human exploitation of amphibians: direct and indirect impacts. R. D. Semlitsch, editor. Amphibian Conservation. Smithsonian Institution, Washington.
  5.  International Union for Conservation of Nature and Natural Resources (IUCN).
  6. Chan, S. (2012, August 7). Study finds a new pathway for invasive species – science teachers. Oregon State University, press release.