IRIS

Tributyltin oxide (TBTO)

CASRN 56-35-9

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (33 pp, 205 K) last updated: 09/01/1997

System RfD (mg/kg-day) Basis PoD Composite UF Confidence
Immune 3 x 10-4 Immunosuppression BMD10 : 3 x 10-2
mg/kg-day
100 High

 


Reference Concentration for Inhalation Exposure (RfC) (PDF) (33 pp, 205 K) last updated: 09/01/1997
Information reviewed but value not estimated.

 

Cancer Assessment

Weight of Evidence for Cancer (PDF) (33 pp, 205 K) last updated: 09/01/1997

WOE Characterization Framework for WOE Characterization
D (Not classifiable as to human carcinogenicity) Guidelines for Carcinogen Risk Assessment (US EPA, 1986)
Carcinogenic potential cannot be determined Proposed Guidelines for Carcinogen Risk Assessment (US EPA, 1996)
Basis:
  • There are no data in humans concerning development of cancer following exposure to tributyltin oxide (TBTO). Cancer bioassays following oral exposure have been conducted in rats and mice. Because of the questionable data from the bioassay in rats, EPA assigns TBTO to the "cannot be determined" category [U.S. EPA, 1996 (proposed)].
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (33 pp, 205 K)

Not assessed under the IRIS Program.

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (33 pp, 205 K)

Not assessed under the IRIS Program.

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