Libby Amphibole Asbestos

Reference Dose for Oral Exposure (RfD) (PDF) (36 pp, 359 K) Last Updated: 12/08/2014

Not assessed under the IRIS Program.

Reference Concentration for Inhalation Exposure (RfC) (PDF) (36 pp, 359 K) Last Updated: 12/08/2014

Weight of Evidence for Cancer (PDF) (36 pp, 359 K) Last Updated: 12/08/2014

• Under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 2005a), Libby Amphibole asbestos (LAA) is "carcinogenic to humans" following inhalation exposure based on epidemiologic evidence that shows a convincing association between exposure to LAA fibers and increased lung cancer and mesothelioma mortality.
• This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (36 pp, 359 K)

Not Assessed under the IRIS Program.

Inhalation Unit Risk: 1.7 x 10^-1 per fiber/cc
Extrapolation Method: Linear low dose extrapolation below the POD.
Tumor site(s): Respiratory
Tumor type(s): Cancer mortality from lung cancer and mesothelioma (Sullivan, 2007)