Mercury is a naturally occurring, highly toxic heavy metal. In the U.S., the biggest source of mercury pollution is coal-fired power plants. Mercury occurs naturally in coal in small quantities, and when coal is burned for energy, it’s released into the air. From there, mercury falls into rivers and lakes, entering the food chain.

In waterways, microbes convert mercury into methylmercury, which accumulates in fish. Methylmercury concentrations in fish can be up to 100 million times greater than the concentration in water. When humans eat fish, mercury gets into our bodies. There is no safe level of mercury consumption.

Mercury can harm human health in a variety of ways. It’s especially dangerous for developing babies and children’s brains. When pregnant women eat contaminated fish, mercury can cross the placenta and impact children’s ability to walk, talk, read, and learn. It can also cause behavioral issues. Mercury is linked to cardiovascular problems too, including increased risk of heart attacks.

The majority of the top mercury-emitting coal-fired plants today are located within 50 to 100 miles of large population centers, some in areas already contending with poor air quality. Black, Brown, low-income, and Indigenous populations bear a disproportionate burden of their mercury pollution and adverse health impacts. An outsize number of Black people in the United States live within 30 miles of a coal-fired power plant.

In addition to living closest to smokestacks, some communities are at higher risk for ingesting mercury as they traditionally eat more fish than others. Tribal communities are among the highest risk groups for mercury contamination from fish consumption.

Moms Clean Air Force worked hard for MATS to be implemented back in 2012. MATS has proved to be an effective pollution prevention program, protecting pregnant women and babies from mercury as well as other poisonous emissions: lead, arsenic, dioxin, acid gases, and cancer-causing chromium, nickel, and selenium. MATS has helped ensure 90% of the mercury from coal burned in power plants doesn’t get released into our air. EPA estimates that MATS saves up to 11,000 lives and prevents thousands of heart attacks, asthma attacks, and hospital and emergency room visits yearly.

The economic benefits of MATS are equally substantial: an estimated $90 billion a year. Utilities have found implementing MATS less expensive than predicted, and polluting coal plants that were too old and dilapidated to upgrade with the “scrubber” technology that curbs emissions were instead shut down. This is a big win against climate change, not just mercury pollution.