Cancer risks for asbestos inhalation vs. ingestion

There is not enough evidence to conclude whether inhalation of asbestos increases the risk of cancers at sites other than the lungs, pleura, and abdominal cavity.

Ingestion of asbestos causes little or no risk of non-cancer effects. There is some evidence, however, that acute oral exposure might induce precursor lesions of colon cancer and that chronic oral exposure might lead to an increased risk of gastrointestinal tumors.

Skin nodules (corns) from handling asbestos-containing materials can also occur.

ATSDR considers the inhalation route of exposure to be the most significant in the current evaluation of sites that received Libby vermiculite. Exposure scenarios that are protective of the inhalation route of exposure should be protective of dermal and oral exposures.

There is general acceptance in the scientific community that fiber length as well as fiber mineralogy influence asbestos toxicity. Fiber length may play an important role in clearance and mineralogy may affect both biopersistence and surface chemistry.