Jump to main content.

Arsenic, inorganic Quickview (CASRN 7440-38-2)

Health assessment information on a chemical substance is included in IRIS only after a comprehensive review of toxicity data by U.S. EPA health scientists from several Program Offices, Regional Offices, and the Office of Research and Development.

Disclaimer: This QuickView represents a snapshot of key information. We suggest that you read the IRIS Summary to put this information into complete context.

For definitions of terms in the IRIS Web site, refer to the IRIS Glossary.

Status of Data for Arsenic, inorganic

File First On-Line: 02/10/1988; Last Significant Revision: 06/01/1995

Category (section)
Last Revised
Oral RfD Assessment Yes 09/01/1991
Inhalation RfC Assessment No
Carcinogenicity Assessment Yes 06/01/1995
Under Re-Assessment
  • 7440-38-2
  • Arsenic
  • Gray-arsenic
  • Arsenic, inorganic
  • Arsenic, inorganic
Revision History
Date Section Description
02/11/2000 II.C.2. Corrected alignment of unit risks in table with corresponding studies
Chronic Health Hazard Assessments for Noncarcinogenic Effects

Reference Dose for Chronic Oral Exposure (RfD)

Critical Effect
Point of Departure*
Hyperpigmentation, keratosis and possible vascular complications NOAEL : 8 x10-4 mg/kg-day 3 3 x10-4 mg/kg-day

* The Point of Departure listed serves as a basis from which the Oral RfD was derived. See Discussion of Conversion Factors and Assumptions for more details.

Top of page

Reference Concentration for Chronic Inhalation Exposure (RfC)

Not Assessed under the IRIS Program.

Top of page

Carcinogenicity Assessment for Lifetime Exposure
  • Weight-of-Evidence Characterization
    • A (Human carcinogen)
  • Weight-of-Evidence Narrative:
    • Based on sufficient evidence from human data. An increased lung cancer mortality was observed in multiple human populations exposed primarily through inhalation. Also, increased mortality from multiple internal organ cancers (liver, kidney, lung, and bladder) and an increased incidence of skin cancer were observed in populations consuming drinking water high in inorganic arsenic.
    • This may be a synopsis of the full weight-of-evidence narrative. See IRIS Summary.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure

Oral Slope Factor(s)
Extrapolation Method
1.5 per mg/kg-day Time- and dose-related formulation of the multistage model
Drinking Water Unit Risks
5x10-5 per µg/L
Risk Level
E-4 (1 in 10,000) 2 µg/L
E-5 (1 in 100,000) 2x10-1 µg/L
E-6 (1 in 1,000,000) 2x10-2 µg/L

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure

Inhalation Unit Risk(s)
Extrapolation Method
4.3 x10-3 per µg/m3 Absolute-risk linear model

Inhalation Concentrations at Specified Risk Levels

Risk Level
E-4 (1 in 10,000) 2x10-2 µg/m3
E-5 (1 in 100,000) 2x10-3 µg/m3
E-6 (1 in 1,000,000) 2x10-4 µg/m3

Top of page

Recent Additions | Advanced Search | IRIS Home | Environmental Assessment | Research

Local Navigation

Jump to main content.