Arsenic, Inorganic

CASRN 7440-38-2

IRIS Toxicological Review of Inorganic Arsenic (Preliminary Assessment Materials, 2014)

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In April 2014, EPA released the draft literature searches and associated search strategies, evidence tables, and exposure response arrays for inorganic arsenic (iAs) to obtain input from stakeholders and the public prior to developing the draft IRIS assessment. Specifically, EPA was interested in comments on the following:
  • Draft literature search strategies
    • The approach for identifying studies
    • The screening process for selecting pertinent studies
    • The resulting list of pertinent studies
  • Preliminary evidence tables
    • The process for selecting studies to include in evidence tables
    • The quality of the studies in the evidence tables
The literature search strategy, which describes the processes for identifying scientific literature, contains the studies that EPA considered and selected to include in the evidence tables. The preliminary evidence tables and exposure-response arrays present the key study data in a standardized format. The evidence tables summarize the available critical scientific literature. The exposure-response figures provide a graphical representation of the responses at different levels of exposure for each study in the evidence table.


U.S. EPA. IRIS Toxicological Review of Inorganic Arsenic (Preliminary Assessment Materials, 2014). U.S. Environmental Protection Agency, Washington, DC, EPA/630/R-14/101, 2014.

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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
01-1988EPA published the IRIS Health Hazard Assessment for Inorganic Arsenic.
02-1999NRC reviewed the 1988 IRIS assessment and the available health data for inorganic arsenic and made recommendations for updating the cancer assessment in Arsenic in Drinking Water.
03-2001NRC updated the NRC (1999) report and evaluated the toxicological risk and health effects of arsenic as relevant to the 2001 Arsenic Rule in Arsenic in Drinking Water – 2001 Update.
04-2001NRC reviewed the 2001 Primary Drinking Water Standard for inorganic Arsenic and made recommendations for applying epidemiologic data in the cancer health assessment.
05-2003EPA started a reassessment of the IRIS Toxicological Review.
06-Jul 2005EPA released the draft IRIS inorganic arsenic assessment in July 2005 for public comment and peer review.
07-Jun 2007Science Advisory Board (SAB) posted a response to the 2005 EPA reassessment of inorganic arsenic (cancer).
08-Oct 2008Draft IRIS Toxicological Review for Inorganic Arsenic (cancer) submitted to OMB for interagency review.
09-Jun 2009EPA hosted an interagency science consultation on the draft IRIS Toxicological Review of Inorganic Arsenic.
10-Feb 2010EPA released the draft IRIS Toxicological Review for Inorganic Arsenic (cancer) to SAB and simultaneously to the public for review and comment, focusing on EPA’s responses to the SAB (2007) report.
11-Oct 2010EPA released the revised draft IRIS inorganic arsenic assessment 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 Oct 25, 2010], and SAB completed its review of the draft assessment.
12-2011Congress directed EPA to contract with the National Research Council (NRC) to review the draft assessment.
13-Nov 2012EPA released scoping and problem formulation materials for the IRIS assessment of inorganic arsenic for public comment and discussion.
14-Jan 2013EPA held a public planning and scoping meeting for development of a new IRIS Toxicological Review of Inorganic Arsenic.
15-Mar 2013EPA held eight science issues public webinars (Mar–July).
16-May 2013EPA submitted a draft Assessment Development Plan (ADP) and preliminary assessment materials to NRC for review.
17-Nov 2013NRC released the interim report, Critical Aspects of EPA's IRIS Assessment of iAs and provided recommendations; NRC supported EPA's plan.
18-Apr 2014EPA held a public science meeting to present and encourage comments on the ADP, preliminary assessment materials, and key science issues.
19-Jun 2014EPA hosted an IRIS public science meeting on June 25-27, 2014, to provide an opportunity for the public to give input and participate in an open discussion regarding preliminary materials that were prepared for inorganic arsenic (iAs), prior to the development of the draft assessment.
21-Dec 2015The National Academies of Science hosted a meeting on the review of EPA's IRIS Toxicological Assessment of Inorganic Arsenic (Preliminary Meeting Materials.


The draft document is scheduled to be reviewed by the National Academy of Sciences in 2018.

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