US EPA

In October 2023, the IRIS Program released the draft IRIS Toxicological Review of Inorganic Arsenic for public comment and external peer review. The IRIS assessment of inorganic arsenic will undergo an independent external scientific peer review managed by EPA’s Science Advisory Board (SAB). Additional information about the peer review meeting can be found on the SAB website.

U.S. EPA. IRIS Toxicological Review of Inorganic Arsenic (Public Comment and External Review Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-23/166, 2023.

Inorganic arsenic is used for hardening copper and lead alloys. It also is used in glass manufacturing as a decolorizing and refining agent, as a component of electrical devices, in the semiconductor industry, and as a catalyst in the production of ethylene oxide. Arsenic compounds are used as a mordant in the textile industry, for preserving hides, as medicinals, pesticides, pigments, and wood preservatives.

Arsenic is also found naturally in the environment and is typically present in soil and water at detectable levels. Sources of human exposure to inorganic arsenic include drinking water, diet, air, and soils (which can contain naturally occurring arsenic or contamination from anthropogenic sources). This draft IRIS health assessment addresses cancer and non-cancer human health effects that may result from chronic exposure to this chemical.

Date	Description
01-1988	EPA published the IRIS Health Hazard Assessment for Inorganic Arsenic.
02-1999	NRC reviewed the 1988 IRIS assessment and the available health data for inorganic arsenic and makes recommendations for updating the cancer assessment.
03-2001	NRC updated the NRC (1999) report and evaluated the toxicological risk and health effects of arsenic as relevant to the 2001 Arsenic Rule.
04-2001	NRC reviewed the 2001 Primary Drinking Water Standard for inorganic Arsenic and EPA’s supporting risk assessment and makes recommendations for applying epidemiologic data in the cancer health assessment.
05-2003	EPA started a reassessment of the IRIS assessment for inorganic arsenic.
06-Jul 2005	EPA released the draft IRIS inorganic arsenic assessment in July 2005 for public comment and peer review.
07-Jun 2007	Science Advisory Board (SAB) posted a response to the 2005 EPA reassessment of inorganic arsenic (cancer).
08-Oct 2008	Draft IRIS Toxicological Review for Inorganic Arsenic (Cancer) submitted to OMB for interagency review.
09-Jun 2009	EPA hosted an interagency science consultation on the draft IRIS Toxicological Review of Inorganic Arsenic (cancer).
10-Feb 2010	EPA released the revised draft IRIS inorganic arsenic assessment (cancer) for public comment and peer review, SAB announced public teleconference to conduct a quality review of the draft report to be held on November 22, 2010. [Federal Register Notice Oct 25, 2010], and SAB completed its review of the draft assessment.
11-Oct 2010	SAB announced a public teleconference to conduct a quality review of the draft report to be held on November 22, 2010. [Federal Register Oct 25, 2010]
12-2011	Congress directed EPA to contract with the National Research Council (NRC) to review the draft assessment (cancer and noncancer).
13-Jan 2013	EPA held a public planning and scoping meeting for development of a new IRIS Toxicological Review of Inorganic Arsenic (cancer and noncancer).
14-2013	EPA held eight science issues public webinars (Mar–July).
15-May 2013	EPA submitted a draft Assessment Development Plan (ADP) and preliminary assessment materials to NRC for review.
16-Nov 2013	NRC released the interim report, Critical Aspects of EPA’s IRIS Assessment of iAs and provided recommendations; NRC supported EPA’s plan.
17-Jun 2014	EPA held a public science meeting to present and encourage comments on the ADP, preliminary assessment materials, and key science issues.
18-Apr 2015	EPA released a revised ADP and other preliminary materials and held two public meetings (webinars).
19-Dec 2015	The National Academies of Science hosted a meeting on the review of EPA's IRIS Toxicological Assessment of Inorganic Arsenic (Preliminary Meeting Materials).
20-May 2019	EPA released the Updated Problem Formulation and Systematic Review Protocol for the IRIS inorganic Arsenic Assessment. EPA posted an errata sheet outlining an update that was made to the protocol and posted on this site on June 20, 2019. [Federal Register Notice May 28, 2019]
21-Jul 2019	EPA posted the summary of public comments document received on the IRIS inorganic arsenic protocol.
22-Nov 2022	EPA sent an interagency science consultation inorganic arsenic draft for review and comment.
23-Oct 2023	EPA release the draft IRIS Toxicological Review of Inorganic Arsenic for a 60-day public comment period and external peer review. EPA also released the interagency science consultation comments from reviewers. [Federal Register Notice: Oct 16, 2023]
24-Dec 2023	EPA released BMD Model Code and BMD Modeling Results provided for the draft IRIS Toxicological Review of Inorganic Arsenic for a 15-day comment period. [Federal Register Notice Dec 29, 2023]

The toxicological review of inorganic arsenic was released for a 60-day public comment period and external peer review. Following the external peer review meeting, the assessment will be revised, taking into consideration all public and external peer review comments received.

If you have a disability and the format of any material on our web pages interferes with your ability to access the information, please contact Dahnish Shams (shams.dahnish@epa.gov) AND hotline.iris@epa.gov. To enable us to respond in a manner most helpful to you, please indicate the nature of the accessibility problem, the web address of the requested material, your preferred format in which you want to receive the material (electronic format (ASCII, etc.), standard print, large print, etc.), and your contact information.

This download(s) is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy.

• IRIS Toxicological Review of Inorganic Arsenic (Public Comment and External Review Draft) (PDF)  (264 pp, 14 MB, about PDF)
• IRIS Toxicological Review of Inorganic Arsenic (Public Comment and External Review Draft) Supplemental Information (PDF)  (315 pp, 8 MB, about PDF)
• Final Charge Questions for External Reviewers (Jan.) (PDF)  (6 pp, 194 KB, about PDF)

If you have a disability and the format of any material on our web pages interferes with your ability to access the information, please reach out to us using the Contact us about IRIS form for assistance. To enable us to respond in a manner most helpful to you, please indicate the nature of the accessibility problem, the web address of the requested material, your preferred format in which you want to receive the material (electronic format (ASCII, etc.), standard print, large print, etc.), and your contact information.

• Updated Problem Formulation and Systematic Review Protocol for the Inorganic Arsenic IRIS Assessment
• IRIS Toxicological Review of Inorganic Arsenic (Interagency Science Consultation Draft, 2022)
• Bmd Model Code and Bmd Modeling Results for the Inorganic Arsenic IRIS Assessment (External Review Draft)

• Primary Literature Search References Sorted By Author (Inorganic Arsenic)
• Dose-Response Model Code and Results

• FR Notice: Dec 29, 2023
• FR Notice: Oct 16, 2023

Comments on the assessment may be submitted and reviewed using the Docket ID EPA-HQ-ORD-2012-0830