IRIS

Nitrobenzene

CASRN 98-95-3

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (30 pp, 257 K) last updated: 02/06/2009

System RfD (mg/kg-day) Basis PoD Composite UF Confidence
Hematologic 2 x 10-3 Increased methemoglobin levels BMDL (1SD): 1.8
mg/kg-day
1000 Medium

 


Reference Concentration for Inhalation Exposure (RfC) (PDF) (30 pp, 257 K) last updated: 02/06/2009

System RfC (mg/m3) Basis PoD Composite UF Confidence
Nervous, Respiratory 9 x 10-3 Bronchiolization of the alveoli and olfactory degeneration BMCL10 (HEC): 0.26
mg/m3
30 Medium
Nervous, Respiratory 9 x 10-3 Bronchiolization of the alveoli and olfactory degeneration BMCL10 (HEC): 0.26
mg/m3
30 Medium

 

Cancer Assessment

Weight of Evidence for Cancer (PDF) (30 pp, 257 K) last updated: 02/06/2009

WOE Characterization Framework for WOE Characterization
Likely to be carcinogenic to humans (Combined route) Guidelines for Carcinogen Risk Assessment (US EPA, 2005)
Basis:
  • Under the Guidelines for Carcinogen Risk Assessment (U.S. EPA, 2005a), nitrobenzene is classified as "likely to be carcinogenic to humans" by any route of exposure.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (30 pp, 257 K)

Not Assessed under the IRIS Program.


Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (30 pp, 257 K)

Inhalation Unit Risk: 4 x10 -5 per µg/m3
Extrapolation Method: Multistage model with linear extrapolation from the POD (LEC10).
Tumor site(s): Hepatic, Urinary, Endocrine
Tumor type(s): Liver hepatocellular adenomas or carcinomas, kidney tubular adenomas or carcinomas, thyroid follicular cell adenomas or carcinomas (CIIT (1993))


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