What Is Lithium?

The EPA says lithium is a naturally occurring metal in the crust of the Earth that may be found at higher concentrations in certain parts of the country, particularly in groundwater in arid locations in the western United States. It lists commercial uses including as a pharmaceutical drug, an industrial chemical catalyst, a sanitizing agent for swimming pools and hot tubs, and increasingly as a component of batteries. The National Institute of Mental Health describes lithium as an effective mood stabilizer approved for the treatment of mania and bipolar disorder, and says health care providers generally ask people taking it to have regular monitoring of lithium levels and kidney and thyroid function.

Lithium shows up in groundwater. A USGS study announced in February 2021 reports that about 45% of public-supply wells and about 37% of US domestic supply wells have lithium concentrations that could present a potential human health risk. A USGS-led study announced in June 2024 estimates that lithium occurs in groundwater at 30 micrograms per liter or higher in public and private wells in much of the western and southwestern states, including Montana, Wyoming, North Dakota, South Dakota, Colorado, Utah, Nevada, Arizona, New Mexico and Texas.

The EPA says its fifth Unregulated Contaminant Monitoring Rule, published December 27, 2021, required sample collection for 30 chemical contaminants, 29 PFAS and lithium, between 2023 and 2025. In an October 2023 technical fact sheet, the EPA gives a health reference level for lithium of 10 micrograms per liter from its Fifth Candidate Contaminant List, and notes that USGS also published a 10 microgram per liter screening level. The EPA also says a lithium-ion battery, or a device containing one, that is thrown in the trash or put in a municipal recycling bin may be damaged or crushed during transport or sorting, creating a fire hazard.