The short answer
Malathion is an insecticide used in agriculture and mosquito control. IARC classifies it as probably carcinogenic, with a suspected link to non-Hodgkin lymphoma; the EPA's assessment differs. Following label safety steps reduces exposure.
Malathion is classified as a probable human carcinogen (IARC Group 2A).
People are mainly exposed by applying it as an insecticide or through low-level food residues.
It is most strongly linked to a debated possible link to non-Hodgkin lymphoma.
A carcinogen classification describes hazard — whether something can cause cancer — not your personal risk at a given exposure.
Choose how you want to understand this
The full explanation.
The simple version
Malathion is an insecticide used on crops, in mosquito-control spraying, and in some lice treatments. IARC classifies it as a probable carcinogen, while the EPA has reached a different conclusion. Applicators face the most exposure, and label safety steps reduce it.
What malathion is
Malathion is an organophosphate insecticide. IARC classified it as probably carcinogenic (Group 2A) in 2015, citing limited human evidence for non-Hodgkin lymphoma. The EPA classifies it differently, an example of agencies weighing the same evidence and reaching different conclusions.
How people are exposed
Common ways people come into contact with it:
- Applying malathion in agriculture or mosquito-control programs
- Low-level residues on some foods
- Some medicated lice treatments
The cancer connection
IARC links malathion most closely to non-Hodgkin lymphoma, with limited human evidence. Assessments by other agencies differ.
The International Agency for Research on Cancer (IARC), the cancer arm of the World Health Organization, places malathion in Group 2A, probably carcinogenic to humans — meaning the evidence in people is limited but there is strong support from animal or mechanistic studies (evaluated in 2015).
Hazard is not the same as risk
It helps to separate two ideas that are easy to mix up: hazard and risk. When an agency lists malathion as a carcinogen, it is making a statement about hazard — whether the substance is capable of causing cancer under some conditions. It is not, by itself, a statement about your personal risk, which depends on how much you are exposed to, for how long, and other factors. Two substances in the same group can carry very different real-world risks. The label answers "can it cause cancer?" — not "how likely is it to cause cancer for me?"
How to lower your exposure
- Follow label directions and wear protection when applying
- Wash produce and eat a varied diet
- Reduce time in freshly sprayed areas
- Use lice treatments as directed
If you are looking at your overall cancer risk, small, steady steps add up. See our overview of cancer prevention and what raises cancer risk to put any single exposure in context.
The bottom line
Malathion is a probable human carcinogen (IARC Group 2A). The most important thing you can do is understand where exposure comes from and take reasonable steps to reduce it, without losing sleep over a single label. Focus your energy on the biggest, most controllable risks in your own life.
Words to know
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Common questions
▸Does malathion cause cancer?
Probably. Malathion is classified as a probable human carcinogen: the evidence in people is limited, but animal and laboratory studies support a link. "Probable" means suspected on solid grounds, not proven.
▸How are people exposed to malathion?
Most exposure happens by applying it as an insecticide or through low-level food residues.
▸Which cancers are linked to malathion?
It is most strongly linked to a debated possible link to non-Hodgkin lymphoma.
▸How can I reduce my exposure to malathion?
The main steps are following label safety steps and washing produce.
▸Does a carcinogen label mean I will get cancer?
No. A classification is about hazard — whether malathion can cause cancer under some conditions — not a prediction that any one exposed person will develop cancer. Your actual risk depends on the amount and length of exposure and other factors.
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