IRIS

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (7 pp, 310 K) Last Updated: 08/13/2021

System RfD (mg/kg-day) Basis PoD Composite UF Confidence
Urinary 4 x 10 -1 Increased severity of nephropathy BMDL 10 (HED): 43.2
mg/kg-day
100 Medium

 


Reference Concentration for Inhalation Exposure (RfC) (PDF) (7 pp, 310 K) Last Updated: 08/13/2021

System RfC (mg/m3) Basis PoD Composite UF Confidence
Urinary 5 Increased severity of nephropathy BMCL 10 (HEC): 491
mg/m3
100 Medium

 

Cancer Assessment

Weight of Evidence for Cancer (PDF) (7 pp, 310 K) Last Updated: 08/13/2021

WOE Characterization Framework for WOE Characterization
Suggestive evidence of carcinogenic potential Guidelines for Carcinogen Risk Assessment (U.S. EPA, 2005)
Basis:
  • Under EPA’s Guidelines for Carcinogen Risk Assessment (U.S. EPA, 2005), tert-butyl alcohol has “suggestive evidence of carcinogenic potential” for all routes of exposure based on some evidence in animals.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (7 pp, 310 K)

Suggestive evidence of carcinogenic potential

Oral Slope Factor: 5 x 10-4 mg/kg-day (OSF based on increasing thyroid tumors in mice. ) Tumor site(s): Urinary, Endocrine
Tumor type(s): Renal adenomas and carcinomas, thyroid adenomas ((NTP, 1995))



Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (7 pp, 310 K)

No PBPK model of tert-butyl alcohol in mice is available; therefore route to route extrapolation (oral to inhalation) cannot be performed at this time.

Additional EPA toxicity information may be available by visiting the following sites:

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