IRIS

Chromium(VI)

CASRN 18540-29-9 | DTXSID7023982

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (34 pp, 203 K) Last Updated: 09/03/1998

System RfD (mg/kg-day) Basis PoD Composite UF Confidence
Other 3 x 10 -3 None reported NOAEL (ADJ): 2.5
mg/kg-day
300
MF: 3
Low

 


Reference Concentration for Inhalation Exposure (RfC) (PDF) (34 pp, 203 K) Last Updated: 09/03/1998

System RfC (mg/m3) Basis PoD Composite UF Confidence
Respiratory 8 x 10 -6
(Chromic acid mists and dissolved Cr(VI) aerosols)
Nasal septum atrophy LOAEL (ADJ): 7.14 x 10-4
mg/m3
90 Low
Respiratory 1 x 10 -4
(Cr(VI) particulates)
Lactate dehydrogenase in bronchioalveolar lavage fluid BMCL 10 (HEC): 3.4 x 10-2
mg/m3
300 Medium

 

Cancer Assessment

Weight of Evidence for Cancer (PDF) (34 pp, 203 K) Last Updated: 09/03/1998

WOE Characterization Framework for WOE Characterization
A (Human carcinogen) (Inhalation route) Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986)
D (Not classifiable as to human carcinogenicity) (Oral route) Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986)
Carcinogenic potential cannot be determined (Oral route) Proposed Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1996)
Known/likely human carcinogen (Inhalation route) Proposed Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1996)
Basis:
  • Under the current guidelines (EPA, 1986), Cr(VI) is classified as Group A - known human carcinogen by the inhalation route of exposure. Carcinogenicity by the oral route of exposure cannot be determined and is classified as Group D. Under the proposed guidelines (EPA, 1996), Cr(VI) would be characterized as a known human carcinogen by the inhalation route of exposure on the following basis. The oral carcinogenicity of Cr(VI) cannot be determined. No data were located in the available literature that suggested that Cr(VI) is carcinogenic by the oral route of exposure.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (34 pp, 203 K)

Information reviewed but value not estimated.


Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (34 pp, 203 K)

Inhalation Unit Risk: 1.2 x 10-2 per µg/m3
Extrapolation Method: Multistage, extra risk
Tumor site(s): Respiratory
Tumor type(s): Lung cancer (Mancuso, 1975)

Program Outlook Details

Public Assessment Materials Date
Problem Formulation Materials/IRIS Assessment Plan Aug-2014
Preliminary Assessment Materials/Systematic Review Protocol Mar-2019
Public Comment Oct-2022
External Peer Review Dec-2022
Post Final Assessment TBD

Note: Any future dates displayed in the table above should be considered estimates and are subject to change. Once the external peer review is complete, estimated dates for release of the final assessment will be published. For the latest information on the status of this assessment, please refer to the IRIS Program Outlook. To access assessment documents, meeting materials or other supporting documents related to this assessment, visit the Chemical Documents tab. For more information about the development process, visit the IRIS Process page.

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