IRIS

1,3,5-Trimethylbenzene

CASRN 108-67-8

Health Hazard Assessments for Effects Other than Cancer

Reference Dose for Oral Exposure (RfD) (PDF) (10 pp, 323 K) last updated: 09/09/2016

System RfD (mg/kg-day) Basis PoD Composite UF Confidence
Nervous 1 x 10-2 Decreased pain sensitivity in male Wistar rats BMDL1SD (HED): 3.5
mg/kg-day
300 Low

 


Reference Concentration for Inhalation Exposure (RfC) (PDF) (10 pp, 323 K) last updated: 09/09/2016

System RfC (mg/m3) Basis POD Composite UF Confidence
Nervous 6 x 10-2 Decreased pain sensitivity in male Wistar rats BMDL1SD(HEC): 18.15 mg/m3 300 Low/Medium

 

Cancer Assessment

Weight of Evidence for Cancer (PDF) (10 pp, 323 K) last updated: 09/09/2016

WOE Characterization Framework for WOE Characterization
Inadequate information to assess carcinogenic potential Guidelines for Carcinogen Risk Assessment (US EPA, 2005)
Basis:
  • Under the Guidelines for Carcinogen Risk Assessment (U.S. EPA 2005), there is “inadequate information to assess carcinogenic potential” of TMBs. This characterization is based on the fact that there is no information regarding the carcinogenicity of TMBs in humans and that the only animal study available on the carcinogenicity of 1,2,4‑TMB observed no statistically significant carcinogenic effects. No studies regarding the carcinogenicity of 1,2,3‑TMB or 1,3,5‑TMB were identified in the available scientific literature.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (10 pp, 323 K)

Not assessed under the IRIS Program.

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (10 pp, 323 K)

Not assessed under the IRIS Program.

 


Organ/System-Specific RfCs

System RfC (mg/m3) Basis POD UF Confidence
Developmental 4 Decreased fetal weight NOAEL: 367.75 mg/m3 100 Low/Medium
Other 4 x 10-1 Decreased maternal weight NOAEL: 124.25 mg/m3 300 Low/Medium

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