US EPA

U.S. EPA. IRIS Toxicological Review of Thallium And Compounds (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-08/001F, 2009.

Thallium exists in monovalent (Tl⁺¹) and trivalent (Tl⁺³) states. Thallium is released to the environment through the combustion of fossil fuels, refinement of oil fractions, the smelting of ferrous and non-ferrous ores, and by some other industrial processes such as cement production and brick works. In the past, thallium was used as a depilatory agent and as a treatment for ringworm, venereal diseases, TB, and malaria. It was banned for use as a pesticide in the United States in 1972. Currently, thallium compounds are used in the semiconductor industry, the manufacture of optic lenses and low-melting glass, low-temperature thermometers, alloys, electronic devices, mercury lamps, fireworks, and imitation gems, and clinically as an imaging agent in the diagnosis of certain tumors.

EPA is undertaking an Integrated Risk Information System (IRIS) health assessment for thallium and compounds. IRIS is an EPA database containing Agency scientific positions on potential adverse human health effects that may result from chronic (or lifetime) exposure to chemicals in the environment. IRIS contains chemical-specific summaries of qualitative and quantitative health information in support of two steps of the risk assessment paradigm, i.e., hazard identification and dose-response evaluation. IRIS assessments are used in combination with specific situational exposure assessment information to evaluate potential public health risks associated with environmental contaminants.

This document has been reviewed in accordance with U.S. Environmental Protection Agency policy and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

• IRIS Toxicological Review and Summary Documents for Thallium and Compounds (PDF)  (163 pp, 1 MB, about PDF)
• IRIS Summary for Thallium and Compounds (PDF)  (16 pp, 137 KB, about PDF)

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• IRIS Toxicological Review of Thallium and Compounds (External Review Draft)