Several chemicals are linked to an increased risk of lymphoma, though most cases involve prolonged or repeated exposure rather than a single contact. The strongest connections involve benzene, certain pesticides, industrial solvents, dioxins, and some ingredients found in everyday consumer products like hair dye and mothballs. The level of risk varies widely depending on the chemical, the duration of exposure, and individual factors like immune health.
Benzene
Benzene is one of the most well-established chemical causes of lymphoma. It is classified as a known human carcinogen and has been linked specifically to non-Hodgkin lymphoma (NHL). Benzene is a colorless liquid with a sweet odor, found in gasoline, cigarette smoke, industrial emissions, and some adhesives and paints. People with the highest exposure tend to work in petroleum refining, rubber manufacturing, or chemical production, though low-level exposure from car exhaust and secondhand smoke is common in the general population.
Inside the body, benzene is broken down into byproducts that damage DNA in blood-forming and immune cells. These byproducts can cause genetic instability, interfere with normal DNA repair, and suppress immune function. That combination of direct genetic damage and a weakened immune system creates conditions where abnormal lymphocytes can survive and multiply unchecked.
Pesticides and Herbicides
Agricultural chemicals are among the most studied risk factors for lymphoma, particularly for people who work with them regularly. Organophosphate insecticides as a class are associated with increased NHL risk, with the strongest evidence pointing to a subtype called follicular lymphoma. The insecticide diazinon, commonly used in farming and formerly in home pest control, roughly doubles the risk of NHL in people who have used it, based on pooled data from the InterLymph Consortium.
Glyphosate, the active ingredient in Roundup, remains one of the most publicly debated chemicals in this category. The International Agency for Research on Cancer (IARC) classified it as “probably carcinogenic to humans” in 2015, citing links to NHL. The U.S. Environmental Protection Agency has disagreed, concluding that glyphosate is “not likely to be carcinogenic to humans” based on what it describes as a more extensive dataset. As of 2025, the EPA is updating its evaluation of glyphosate’s cancer potential. This ongoing disagreement means the question is not fully settled, and courts have awarded billions of dollars to plaintiffs who developed NHL after long-term glyphosate use.
Dioxins and Agent Orange
Dioxins are a group of highly toxic compounds produced as byproducts of industrial processes like waste incineration, paper bleaching, and herbicide manufacturing. The most potent, known as TCDD, is classified by IARC as a known human carcinogen. TCDD was a contaminant in Agent Orange, the defoliant sprayed widely during the Vietnam War.
U.S. veterans exposed to Agent Orange have been recognized by the Department of Veterans Affairs as having elevated risk for several cancers, including NHL. Dioxins persist in the environment for years and accumulate in body fat, meaning exposure effects can emerge long after the initial contact. For the general population, trace dioxin exposure comes primarily through animal fats in the diet, since dioxins concentrate as they move up the food chain.
Trichloroethylene (TCE)
Trichloroethylene is a chlorinated solvent historically used for metal degreasing, dry cleaning, and as an ingredient in adhesives and paint removers. It has been classified as a known human carcinogen, with links to NHL and kidney cancer. A meta-analysis of occupational studies found that workers exposed to TCE had roughly double the risk of NHL compared to unexposed workers, with risk estimates around 2.1 to 2.3 depending on the exposure level.
Interestingly, the data did not show a clear dose-response pattern. Workers with the lowest TCE exposure had similar risk elevations to those with the highest exposure, and neither duration nor cumulative exposure produced a gradient. This unusual pattern suggests that even relatively modest exposure may carry meaningful risk, though it also makes the relationship harder to characterize precisely.
Hair Dye
Long-term use of permanent hair dye is associated with a modest but real increase in NHL risk. A meta-analysis published in Medical Principles and Practice found that frequent hair dye users had a 14% higher risk of NHL overall. The risk climbed with duration: people who used hair dye for 10 to 20 years had about a 20% increase, and those who used it for more than 20 years had a 34% increase. The association was strongest among women, who make up the majority of regular users.
Permanent hair dyes contain aromatic amines and other reactive chemicals that can be absorbed through the scalp. The formulations have changed significantly since the 1980s, when some of the most hazardous ingredients were removed, so the risk from modern products may be lower than what older studies captured. Still, the linear relationship between years of use and NHL risk suggests that cumulative exposure matters.
Household Chemical Exposures
Some common household products contain chemicals that have been linked to lymphoma. Mothballs are one notable example. Their active ingredients, naphthalene and paradichlorobenzene, are among the most frequently detected toxic chemicals in indoor air. Research published in Environmental Health Perspectives found a significant correlation between mothball use and NHL risk, though without a clear dose-response relationship.
Formaldehyde, used in some pressed-wood furniture, flooring, and building materials, is another indoor exposure classified as a known carcinogen. It has been linked to certain blood cancers, though the evidence is strongest for leukemia rather than lymphoma specifically. The common thread among these household exposures is chronic, low-level inhalation in enclosed spaces over years or decades.
How These Chemicals Trigger Lymphoma
Chemicals cause lymphoma through three overlapping mechanisms. The first is direct DNA damage. When reactive chemical byproducts bind to DNA in lymphocytes (the white blood cells that become cancerous in lymphoma), they can cause mutations that disable the cell’s normal growth controls. The second is immune suppression. Many of these chemicals interfere with the immune system’s ability to detect and destroy abnormal cells, giving damaged lymphocytes a survival advantage. The third is chronic inflammation, which creates a microenvironment where damaged cells are more likely to proliferate.
Research on bisphenol A (BPA), a chemical found in some plastics and food container linings, illustrates how these pathways interact. BPA exposure has been shown to cause DNA damage in human cell lines while simultaneously disrupting immune and inflammatory responses. When DNA-damaged lymphoid cells exist in a compromised immune environment, the conditions favor lymphoma development. This dual-hit model, combining genetic damage with immune dysfunction, applies broadly to most chemical causes of lymphoma.
Who Faces the Highest Risk
Occupational exposure accounts for the most significant chemical-related lymphoma risk. Workers in petroleum refining, rubber manufacturing, agriculture, dry cleaning, and painting encounter higher concentrations of lymphoma-linked chemicals than the general population. Duration matters: most elevated risks appear after years or decades of regular exposure, not brief or one-time contact.
People with already-compromised immune systems face compounding risk. HIV infection and the use of immunosuppressive drugs (such as those taken after organ transplants) are independently established causes of lymphoma. When immune suppression from these conditions overlaps with chemical exposures, the combined effect can be greater than either factor alone. For the general public, the risk from typical environmental levels of any single chemical is small, but it grows with the number of exposures, their duration, and the presence of other risk factors like viral infections or family history of blood cancers.