- IRIS Summary (PDF) (19 pp, 139 K)
Reference Dose for Oral Exposure (RfD) (PDF) (19 pp, 139 K)
Not assessed under the IRIS Program.
Reference Concentration for Inhalation Exposure (RfC) (PDF) (19 pp, 139 K)
last updated: 11/01/1990
|System||RfC (mg/m3)||Basis||PoD||Composite UF||Confidence|
|Hematologic||1 x 10-3||Methemoglobin increase, spleen toxicity||
Weight of Evidence for Cancer (PDF) (19 pp, 139 K)
last updated: 09/07/1988
|WOE Characterization||Framework for WOE Characterization|
|B2 (Probable human carcinogen - based on sufficient evidence of carcinogenicity in animals)||Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986)|
- Induction of tumors of the spleen and the body cavity in two strains of rat, and some supporting genetic toxicological evidence.
- This may be a synopsis of the full weight-of-evidence narrative.
Oral Slope Factor:
5.7 x 10 -3 per mg/kg-day
Drinking Water Unit Risk: 1.6 x 10 -7 per µg/L
Extrapolation Method: Linearized multistage procedure, extra risk
Tumor site(s): Immune
Tumor type(s): Spleen, combined fibrosarcoma, stromal sarcoma, capsular sarcoma and hemangiosarcoma (CIIT, 1982)
Not Assessed under the IRIS Program.
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