IRIS

Libby Amphibole asbestos

CASRN NA

Noncancer Assessment

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

System RfC (mg/m3) Basis PoD Composite UF Confidence
Respiratory 9 x 10-5 Localized pleural thickening BMCL10 : 2.6 x 10-2
fiber/cc
300 Medium

 

Cancer Assessment

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

WOE Characterization Framework for WOE Characterization
Carcinogenic to humans (Inhalation route) Guidelines for Carcinogen Risk Assessment (US EPA, 2005)
Basis:
  • 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.


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

Inhalation Unit Risk: 1.7 x10 -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)


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