November 16, 2023

EPA Seeks Feedback on Draft Toxicological Review of Inorganic Arsenic

A draft toxicological review of inorganic arsenic from EPA’s Integrated Risk Information System (IRIS) program is available for public comment through Dec. 15. According to the agency, this draft health assessment is based on a “comprehensive review of the available scientific literature” and seeks to address both cancer and non-cancer health effects that may result from chronic exposure to inorganic arsenic. Health effects discussed in the draft document include cancers of the bladder and lung as well as diseases of the circulatory system, pregnancy and birth outcomes, diabetes, and neurodevelopmental effects. EPA’s draft also summarizes the chemical properties of inorganic arsenic and includes information about hazard identification and dose-response assessment.

Inorganic arsenic is used in a variety of industries for hardening copper and lead alloys, as a component of electrical devices, and as a catalyst in the production of ethylene oxide. In glass manufacturing, inorganic arsenic is used as a decolorizing and refining agent, and in the textile industry, it’s used as a mordant or dye fixative. Inorganic arsenic is formed when arsenic is combined with other elements such as oxygen, chlorine, and sulfur, and workplace exposures typically occur through inhalation, ingestion, dermal contact, or eye contact, according to OSHA.

EPA first published its IRIS health hazard assessment for inorganic arsenic in 1988 and has classified the chemical as a human carcinogen. The agency’s reference dose for oral exposure to inorganic arsenic was last updated in 1991, and the weight of evidence for cancer was last updated in 1995. A new IRIS toxicological review of the chemical has been in development for more than 10 years. EPA’s IRIS webpage for the chemical details the history and chronology of its efforts related to inorganic arsenic.

EPA’s public comment period coincides with an external peer review of the draft toxicological review of inorganic arsenic. Next, EPA will revise its assessment to address public comments and recommendations from peer reviewers. The new draft document, supplemental information, and EPA’s questions for external reviewers are available for download from its IRIS page for inorganic arsenic. Instructions for submitting comments and more information about the peer review can be found in the Federal Register.