originally published for CBSHealthwatch.com 07/2001

Americans have been kicking the cigarette habit and staying out of the sun to avoid cancer. That's a good start. But a recent government report, Report on Carcinogens, identifies several other cancer culprits--many of which are in your garage, your medicine cabinet, and even your pantry.

Take mineral oil, for instance. It is found in nearly every cosmetic, oil, and skin cream. And it is also listed as a known carcinogen by the federal government.

But don't panic yet, says Christopher Portier, PhD, acting director of the Environmental Toxicology Program and acting associate director of the National Toxicology Program at the National Institute of Environmental Health Sciences (NIEHS). "If it is on our list it means to some degree it should be suspect. It does not mean in your particular case it is going to cause cancer for you. There are a lot of factors involved in that."

Many of the chemicals listed in the report arguably improve our lives. Before we ban these chemicals, we need to understand more about the risks. According to Graham Colditz, MD, DrPH, director of education at the Harvard Center for Cancer Prevention, "Numerous lifestyle and environmental factors also contribute to cancer through mechanisms that promote cell division and the accumulation of DNA changes that ultimately lead to cancer," he says.

Amount Counts

Amount of exposure to the carcinogen is a risk factor, says Portier. The more you come in contact with the carcinogen, the more risk it becomes to you.

An example of this degree of risk is with the substance cadmium. It is used in fertilizers on golf courses and in batteries. The government report identifies cadmium as a carcinogen in an "occupational setting." "As a general rule occupational exposure is higher," explains Portier.

"The [cadmium in] batteries are a good example. In your day-to-day experience with batteries it is unlike that you are ever going to come in touch with the cadmium." The person who put the cadmium in the battery on the other hand is at a much higher risk.

At what levels, then, are these chemicals carcinogenic and at what levels are they safe? That is where the debate begins.

Scientists first identify carcinogens through their studies in lab animals, for example, and then estimate risk factors for the consumer's more casual use. But it's not all guesswork, says Colditz.

"It is important to remember which cancers some of these agents actually cause. If the agents cause a very rare cancer, then the overall impact on our society is far less than if it causes a common cancer. Remember that half of all cancers diagnosed occur in just four sites--the lung, the colon, the breast, and the prostate. A carcinogen that increases the risk of a very rare cancer, say the nasal passages, though a real cause of cancer, will not have a major impact because the risk of the cancer is so rare in the first place," he says.

Carcinogens in Your Home

The National Toxicology Program at the NIEHS studies chemicals to determine their safety. Their recommendations contribute to the Report on Carcinogens. The following agents are under suspicion of already known to be carcinogens:

Alcohol--Consumption of alcoholic beverages is known to be casually related to cancers of the mouth, pharynx, larynx and esophagus.
Cadmium--This chemical is used in batteries and plastic and synthetic products. The report finds increased risk of lung cancer in workers exposed to cadmium.
Dry-cleaning chemicals--Tetrachloroethylene is used in dry cleaning and textile processing. People who work at dry cleaning companies or use coin-operated laundromats containing dry cleaning machines are exposed to this carcinogen.
Methyleugenol--This flavoring is used in jellies, baked goods, non alcoholic beverages, chewing gun, candy and ice cream.
Mineral oil and coal tars--Mineral oils are primarily used for industrial purposes. However, technical grade and medicinal oils are used in cosmetics and pharmaceuticals. Tar ointments are used for skin ailments.
Mothballs (naphthalene)--The principal ingredient in mothballs is naphthalene. A study in mice found clear evidence that naphthalene causes cancer.
Wood dust--The data suggest that wood dust is carcinogenic in occupational settings. Furniture makers and cabinet manufacturers are at increased risk.

Everything Causes Cancer?

Some people may read this list and shrug, saying, "Everything causes cancer." That's probably too broad, say Portier. "The fairer statement is that everything is toxic in high-enough doses. The amount matters tremendously."

"Consumers thus should not be alarmist in their response,"advises Colditz. "While we can avoid these agents, we should place far greater emphasis on changing lifestyle to reduce overall risk through everyday actions, such as exercise." He also recommends these cancer-fighting strategies:

Avoid cigarette smoke (both active and passive smoke exposure.)
Avoid weight gain.
Increase physical activity.
Reduce red meat intake and eat more fruits and vegetables and whole grain products.
Practice safer sex to avoid exposure to viruses that cause cancer.
Avoid excess alcohol intake (more than two drinks a day for men and one drink a day for women.)
Reduce sun exposure.

Kimberly Nelson is a freelance medical writer.

Reviewed by:
Beth Israel Deaconess Medical Center. Reviewed for medical accuracy by physicians at Beth Israel Deaconess Medical Center (BIDMC), Harvard Medical School. BIDMC does not endorse any products or services advertised on this Web site.