Many of the frogs used for dissection are wild caught, disrupting the balance of ecosystems. Purpose-bred frogs are raised in conditions that encourage disease, which can spread to fragile wild amphibian populations.

The chemical compounds used to preserve animal specimens often contain formaldehyde, a "hazardous air pollutant, water pollutant, and waste constituent," according to the U.S. Environmental Protection Agency. Chemical production, the preserving process, and disposal of both chemicals and animal remains can contaminate water and soil and potentially harm wildlife and humans.

Millions of animals are shipped to schools to be used just one time in the classroom. Next year, millions more will again meet the same fate.

The preservative formaldehyde can be linked to cancers of the throat, lungs, and nasal passages, especially with prolonged or repeated exposure. Children may be more susceptible to the respiratory effects of formaldehyde than adults, according to the Agency for Toxic Substances and Disease Registry.