Globally, up to 126.9 million non-human vertebrate animals are bred, used, and disposed of in the drug, medical, chemical, cosmetic, and household product industries. As in the farmed animal industry, this mass use of animals as resources raises serious environmental impact concerns.

Companies in the U.S – the country that uses the most animals in research and testing in the world – are not required to report the total number of research animals used to the USDA. This makes environmental analysis difficult, but it is still clear that a huge number of animals are used and disposed of in the research industry. The few specific studies on the environmental impact of animal research indicate that the use and disposal of animals contributes to pollution, as well as harming biodiversity and public health.

The researchers of this study set out to examine existing evidence of the environmental impact of animal research, paying particular attention to: Resources used in animal research; waste production in laboratories; sources of pollution; impacts on laboratory workers’ health; biodiversity impacts.

Resources Used in Animal Research

To get an idea of the scale of animal use, the researchers examined their use in toxicity testing, which demonstrates the safety and efficacy of drugs and chemicals. Toxicity tests are most commonly conducted on rats, mice, rabbits, and dogs. A standard series of toxicity tests can use between 6,000 and 12,000 animals and may take years to complete.

Another resource used in animal research is energy. The quantity of energy consumed by research animal facilities is up to ten times greater than offices on a square meter basis. Animal research facilities have very specific, energy-intensive needs, including total fresh air exchanges for ventilation, environmental and space needs of the animals, barrier protection from outside pathogens, lighting, and power-intensive equipment.

A wide range of chemicals are also used throughout animal research and testing, for sanitation, disinfection, sterilization, and animal care. Toxic substances such as irritants, corrosive substances, asphyxiants, neurotoxins, and carcinogens are frequently used for extended time periods and in large quantities.

Waste Production in Laboratories

Millions of animal bodies — as well as supplies such as bedding, caging, needles, and syringes — are disposed of each year. The routine disposal of hazardous waste also produces harmful substances and air pollutants. The most prominent chemically and biologically hazardous waste produced are animal carcasses and tissues that contain toxic chemicals. Toxic carcasses and tissues are most often incinerated, with many animal research facilities maintaining their own incinerators on-site.

Sources of Pollution

Air pollution is produced by the emission of gases resulting from the incineration of animal carcasses and laboratory supplies, many of which contain toxins. The fuel consumption required to maintain the necessary temperatures of such incinerators has led environmental groups to conclude that incineration is not environmentally sound. Although the researchers were unable to calculate what percentage of incinerated waste came from animal research versus other industries, it is still important to address the fact that animal research plays a part in the negative environmental effects of incineration. Incineration is also extremely harmful to human health, causing chronic illness and developmental delays in nearby populations.

In addition, soil contamination and runoff of animal waste can result in ground water contamination, exacerbating the problem of drugs in public water supplies and contaminating public drinking water.

Impacts on Laboratory Workers’ Health

Due to intense air filtration pressures on animal research facilities, allergic reactions and asthma remain major occupational health risks for laboratory workers. Between 11% to 44% of laboratory workers in the U.S. experience allergic reactions to laboratory animals and between 4% to 22% suffer from occupational asthma. Exposure to laboratory animal allergens can be eliminated by reducing animal research and testing with in vitro alternatives.

The inhalation of waste anesthetic gases (WAGs) has also been associated with long-term physical and mental ill health, including headaches, depression, and neurological and reproductive dysfunction. Laboratory acquired infections (LAI) occur through direct or indirect contact with the animals or their waste, equipment, and supplies. Macaques, pigs, dogs, rabbits, mice, and rats present the strongest risk for the transmission of zoonotic disease. Animal researchers have previously been infected with respiratory disease, herpes B, and ringworm.

Biodiversity Impacts

In an era of unprecedented threats to biodiversity, we are losing species at a rate 50 to 500 times higher than natural background rates found in fossil records. Conservation groups have noted that the long-tailed macaque population — the most commonly used monkey in laboratories — is rapidly declining in the wild. Monkeys are often caught in the wild using false permits and are then bred in captivity for use in animal research. The trade in monkeys for research also raises concerns about the growth and spread of animal disease and dangerous pathogens. There are also issues regarding the potential for genetically modified animals to escape and interbreed with, or out-compete wild populations. This would have a disruptive effect on the local environment and indigenous populations.

In general, records and research on the environmental impact of animal testing are extremely limited. To help combat this, the researchers suggest that rats, mice, and birds must be covered under the Animal Welfare Act to begin recording the scope of animal use. 

It is true that the farmed animal industry has a larger contribution to the negative environmental impacts discussed above. However, the environmental impact of the animal research industry has serious negative consequences and cannot be ignored, especially in light of the availability of alternative testing methods. Non-animal methods spare large numbers of animals from pain and distress, and are often less expensive and time-consuming to perform. Non-animal research also promises faster delivery of test results with greater applicability to humans. The research industry, government agencies and other stakeholders must give proper weight to the environmental impacts of animal research when making decisions and considering alternatives to animal research.