Mercury is a naturally occurring metal in the Earth’s crust. As a chemical element, it cannot be created or destroyed. The same amount of mercury has existed since the Earth was formed.
Most human intake of mercury comes from eating certain types of fish or seafood containing a form of mercury called "methylmercury." But there is disagreement among experts over the level of mercury considered safe for public health.
The electric power industry will reduce mercury emissions through compliance with the Mercury and Air Toxics Standards (MATS) rule which went into effect on April 16, 2012. The rule requires all coal-based power plants to reduce mercury emissions, non-mercury hazardous air pollutants (HAPs) and non-mercury metals emissions.