Yes, cadmium is a confirmed human carcinogen. Both the International Agency for Research on Cancer (IARC) and the U.S. National Toxicology Program classify cadmium and cadmium compounds as “known human carcinogens,” placing it in the same category as asbestos and benzene. The classification, first established by IARC in 1993 and independently confirmed by the NTP in 2000, was based on strong epidemiological evidence linking cadmium exposure to lung cancer in occupational settings, along with animal studies showing tumors at multiple tissue sites across several species.
Which Cancers Are Linked to Cadmium
Lung cancer has the strongest and longest-established connection to cadmium, particularly among workers who inhale cadmium dust or fumes. But the list of associated cancers has grown over the decades. The National Cancer Institute now identifies cadmium as primarily associated with lung, prostate, and kidney cancers, with more recent evidence also pointing to pancreatic, breast, bladder, and endometrial cancers.
A 2025 meta-analysis looking specifically at endometrial cancer found that cadmium exposure was associated with a 27% increased risk overall. When researchers looked only at blood cadmium levels, which reflect more recent or ongoing exposure, the risk jumped to 49%. These findings held up across both high-quality and moderate-quality studies and after adjusting for other risk factors.
How Cadmium Damages Cells
Cadmium doesn’t cause cancer the way many other carcinogens do. It isn’t strongly mutagenic on its own, meaning it doesn’t directly rewrite your DNA the way ultraviolet radiation or tobacco smoke chemicals do. Instead, it works through several indirect routes that, over time, push cells toward uncontrolled growth.
One of the most important mechanisms is that cadmium interferes with your body’s ability to fix damaged DNA. Your cells constantly repair small errors that occur during normal division. Cadmium disrupts this process at multiple levels. It blocks a key tumor-suppressing protein (p53) from binding to DNA, which weakens one of your body’s primary defenses against cancer. It also inhibits an enzyme that prevents damaged building blocks from being incorporated into new DNA strands, leading to a gradual buildup of genetic errors.
Cadmium also triggers the production of reactive oxygen species, unstable molecules that damage cell membranes, break DNA strands, and cause chromosomal abnormalities. At the same time, it depletes your cells’ natural antioxidant defenses, particularly a molecule called glutathione, leaving cells more vulnerable to this oxidative damage. The combination of increased DNA damage and reduced repair capacity creates the conditions for cells to accumulate the mutations that drive cancer.
Beyond DNA damage, cadmium stimulates cell division and suppresses apoptosis, the process by which damaged or abnormal cells are programmed to self-destruct. It also alters how genes are switched on and off through changes in DNA methylation, and it activates several growth-promoting genes. Together, these effects help damaged cells survive and multiply when they normally would not.
Why Cadmium Builds Up in Your Body
What makes cadmium particularly dangerous compared to many other toxic metals is how long it stays in your body. The kidneys and liver together hold about 50% of your body’s total cadmium burden, and the metal is excreted extremely slowly. Its half-life in the kidney ranges from 6 to 38 years, meaning that even after decades, only half of what you absorbed may have been eliminated. In the liver, the half-life is 4 to 19 years.
This means cadmium accumulates over a lifetime. Even low-level, chronic exposure can eventually produce significant tissue concentrations. A person who smoked for 20 years in their twenties and thirties is still carrying much of that cadmium in their forties and fifties.
Where Exposure Comes From
Cigarette smoking is the single largest source of cadmium exposure for the general population. Each cigarette contains roughly 0.5 to 1 microgram of cadmium, and the lungs absorb inhaled cadmium far more efficiently than the gut absorbs it from food. Over years of smoking, this adds up substantially.
For nonsmokers, food is the primary route. Cadmium accumulates in soil, and certain crops absorb it readily. Whole grains, leafy vegetables like spinach, potatoes and other root vegetables, and some seeds tend to have higher concentrations. Shellfish, particularly crustaceans and mollusks from contaminated waters, can also be significant sources. None of these foods are dangerous in normal amounts, but people who eat large quantities of high-cadmium foods over many years can develop elevated body levels.
Drinking water is generally a minor contributor. The EPA sets the maximum contaminant level for cadmium in public water systems at 0.005 milligrams per liter (5 parts per billion). Contamination above this level can occur from corroding galvanized pipes, runoff from waste batteries and paints, or discharges from metal refineries.
Occupational Exposure and Higher Risk
Workers in certain industries face cadmium levels far above what the general public encounters. According to OSHA, the highest exposure risks occur in manufacturing and construction, specifically in smelting and refining metals, manufacturing nickel-cadmium batteries, electroplating, welding, painting, and making plastics, coatings, and solar panels. The growing battery recycling industry is an increasing concern.
Less obvious exposure sources include landfill operations, recycling of electronic parts and plastics, composting, waste collection, and municipal waste incineration. In all of these settings, cadmium-containing dust or fumes can be inhaled, which is the most efficient route of absorption and the exposure pathway most strongly linked to lung cancer. OSHA maintains specific standards for cadmium exposure limits across general industry, construction, maritime, and agriculture.
Reducing Your Exposure
Quitting smoking, or never starting, is the single most effective way to lower cadmium exposure. Secondhand smoke also contributes, though to a lesser degree. For dietary exposure, eating a varied diet rather than relying heavily on any single food group naturally limits how much cadmium you absorb. Adequate iron, zinc, and calcium intake can also reduce cadmium absorption in the gut, since cadmium competes with these minerals for the same transport pathways.
If you work in an industry with potential cadmium exposure, proper ventilation, respiratory protection, and following workplace exposure limits are critical. Biological monitoring through blood or urine cadmium levels can track whether protective measures are working. Blood cadmium reflects recent exposure, while urine cadmium better reflects the total amount stored in your body over time.