Pesticides

What you may have heard

Exposure to pesticides can increase the risk of developing cancer.

What science tells us

Pesticides are typically used in food production and to treat insect infestation. Mosquitos, ticks, rats, and mice can carry diseases, and pesticides can be used to limit human exposures to these pests (EPA). 

Epidemiological Evidence

It is very difficult to measure exposure to pesticides, therefore randomized control trials cannot be conducted. Most exposures that could be relevant to cancer risk may have occurred a long time ago, and it is nearly impossible for an individual to accurately report what exposures they may have had many years ago.  Occupational studies have been the most useful in understanding the effects of pesticide in the workplace (for example, among agricultural workers), and many have reported that high exposure to pesticides can increase the risk of many types of cancers such as: brain, breast, kidney, lung, ovarian, pancreatic, and prostate cancer (Bassil et al.).

Laboratory Evidence/ Supportive Evidence

Several pesticides have been shown in toxicology studies to be cancer causing. DDT in laboratory studies was shown to cause tumors in the livers in rats and mice. 

Lindane has shown to be suggestive of causing cancer but requires more data to further evaluate. It was shown to cause lung tumors (Burns et al.)

Glyphosate

Epidemiological Evidence

Most epidemiological studies and the balance of the epidemiological evidence has shown that glyphosate, a common pesticide used to kill weeds, is not carcinogenic in humans (EPA). However, there remains much controversy about these findings and conclusions about the carcinogenic role of glyphosate under usual human exposure levels is not considered resolved by some.

Laboratory Evidence/ Supportive Evidence

Laboratory evidence generally concur with the epidemiological evidence that exposure to glyphosate based pesticides are generally safe among animals (Jarrell et al.). 

IARC Carcinogen Classification: 2A (Probably carcinogenic to humans: Glyphosate)

How to reduce your risk

You can limit the use of pesticides by opting to use non-chemical methods to control the number of pests in the yard. Mechanical traps can be used to catch unwanted insects, and the introduction of beneficial insects into the yard can help reduce the presence of aphids. Ladybugs will reduce the presence of aphids. 

If using pesticides, make sure to follow the instructions on the bottle and wear protective clothing when spraying. Use gloves, protective eyewear, and make sure you are in a well-ventilated area. Keep children, pets, and toys away from the treated areas(NY Health).

Bottom line

Some pesticides are deemed harmful by IARC and the EPA and can cause cancer. While some pesticides like glyphosate are considered safe by the EPA, further research is needed to examine what other individual pesticides may be harmful.

Learn More From These Trusted Sources

Reducing Pesticide Exposure

Cancer and Occupational Exposure

Date

August 22, 2022
Verified/updated: August 22, 2022