Ethnic Americans face a high risk of mercury poisoning, but they don’t always know it. New data from a Sierra Club-commissioned study reveals that high rates of subsistence fishing among minorities contribute to high levels of mercury in the body, which can affect the nervous system, especially in unborn babies and children. According to data released Tuesday from a Sierra Club-commissioned study, nearly a third of Hispanic Americans fish regularly and the majority share their catch with their families.

The result is that Latino anglers in California ingest nearly twice the U.S. EPA’s safe limit of mercury per day, according to a 2009 UC Davis study on subsistence fishing. The data is even worse for Southeast Asian fishers, particularly Laotians, who ingest further two times more mercury than Hispanics.

The previously unreleased data was from a 2008 study of Latinos and the Environment, conducted by pollster Bendixen & Amandi.

Reliance on fish for subsistence, lack of access to transportation to less polluted waters and love of the sport all contribute to the severity of the problem in ethnic communities.

At the same time, only 12 percent of Hispanic Americans listed mercury poisoning among their greatest environmental concerns in the Sierra Club -commissioned study. UC Davis researchers also found that ethnic communities were least likely to be aware of fish contamination.

The Sierra Club is currently publicizing the data as part of a campaign that aims to increase regulation on coal power plants, the largest contributors of mercury contamination in the United States. Once in the air, mercury makes its way into waterways, is absorbed by fish, hooked by fishermen and eaten by humans.

The EPA is currently considering regulating mercury, arsenic and several other toxins emitted from power plant smoke stacks. There are currently no national standards for mercury emissions from power plants.