Chromium(VI)

CASRN 18540-29-9

Toxicological Review (PDF) (70 pp, 195 K)
IRIS Summary (PDF) (34 pp, 203 K)
Status: Chromium(VI) is in step 1 at this time; see Quick Check.

Key IRIS Values
Assessment Status
History

Health Hazard Assessments for Effects Other than Cancer

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

RfD (mg/kg-day)	System	Basis	PoD	Composite UF	Confidence
3 x10^-3	None	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

RfC (mg/m³)	System	Basis	PoD	Composite UF	Confidence
8 x10^-6 (Chromic acid mists and dissolved Cr(VI) aerosols)	Respiratory	Nasal septum atrophy	LOAEL (ADJ): 7.14 x10^-4 mg/m³	90	Low
1 x10^-4 (Cr(VI) particulates)	Respiratory	Lactate dehydrogenase in bronchioalveolar lavage fluid	BMC₁₀ (ADJ): 3.4 x10^-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 (US EPA, 1986)
D (Not classifiable as to human carcinogenicity) (Oral route)	Guidelines for Carcinogen Risk Assessment (US EPA, 1986)
Carcinogenic potential cannot be determined (Oral route)	Proposed Guidelines for Carcinogen Risk Assessment (US EPA, 1996)
Known/likely human carcinogen (Inhalation route)	Proposed Guidelines for Carcinogen Risk Assessment (US 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 x10^-2 per µg/m³
Extrapolation Method: Multistage, extra risk
Tumor site(s): Respiratory
Tumor type(s): Lung cancer (Mancuso, 1975)

Chromium(VI) is being reassessed.

Assessment Manager(s): Catherine Gibbons (gibbons.catherine@epa.gov), Alan Sasso (sasso.alan@epa.gov)

Step	Assessment Materials Released to the Public	Release Date	Public Meeting Date
1	Problem Formulation Materials	04/2014	06/2014
1	Preliminary Assessment Materials	08/2014	10/2014
4	Public Comment Draft	TBD	TBD
4	Peer Review Draft	TBD	TBD
7	Post Final Assessment	TBD