Asbestos: Cancer Health Hazard Information

Cancer Risk:

• A large number of occupational studies have reported that exposure to asbestos via inhalation can cause lung cancer and mesothelioma (a rare cancer of the membranes lining the abdominal cavity and surrounding internal organs).

• Individuals who smoke and are also exposed to asbestos have a greater than additive increased risk of developing lung cancer.

• Several occupational studies have reported an increase in gastrointestinal cancer from inhalation exposure to asbestos and subsequent oral ingestion.

• Long- and intermediate-range asbestos fibers (>5 micrometers (µm)) appear to be more carcinogenic than short fibers (<5 µm).

• Several epidemiological studies have found an association between asbestos in drinking water and cancer of the esophagus, stomach, and intestines; however confounding factors and the short followup time relative to the long latent period for tumor formation make it difficult to interpret the results.

• A series of large-scale lifetime feeding studies in animals reported that intermediate-range asbestos fibers increased the incidence of a benign tumor of the large intestine in male rats, while short-range asbestos fibers showed no significant increase in tumor incidence.

• EPA considers asbestos to be a human carcinogen (cancer-causing agent) and has ranked it in EPA's Group A.

• EPA uses mathematical models, based on human and animal studies, to estimate the probability of a person developing cancer from breathing air containing a specified concentration of a chemical. EPA calculated an inhalation unit risk estimate of 2.3 × 10-1 (fibers/cm3)-1. EPA estimates that, if an individual were to continuously breathe air containing asbestos at an average of 0.000004 fibers/cm3 over his or her entire lifetime, that person would theoretically have no more than a one-in-a-million increased chance of developing cancer as a direct result of breathing air containing this chemical. Similarly, EPA estimates that breathing air containing 0.00004 fibers/cm3 would result in not greater than a one-in-a-hundred thousand increased chance of developing cancer, and air containing 0.0004 fibers/cm3 would result in not greater than a one-in-ten-thousand increased chance of developing cancer.

Courtesy of the EPA