US Environmental Protection Agency (EPA) has proposed the first national standards for mercury, arsenic and other toxic air pollution from power plants.

Many power plants would need to install available pollution control technologies to cut harmful emissions of mercury, arsenic, chromium, nickel and acid gases to abide by the standards.

The proposed rule provides up to four years for facilities to meet the standards and, once fully implemented, will prevent 91% of mercury in coal from being released into the air.

Toxic air pollutants such as mercury from coal-fired and oil-fired power plants are known to cause neurological damage including lower IQ in children in the womb and during early development.

The standards also address emissions from other toxic metals such as arsenic, chromium and nickel that harm the environment and pollute lakes, streams and aquatic life.

Power plants are the largest source of several toxic air pollutants that cause half of mercury and more than half of acid gas emissions in the US.

Coal-fired power plants are responsible for 99% of mercury emissions in the power sector.

The total health and economic benefits of the standard are estimated to be about $140bn annually.

A final rule on mercury emission standards is expected to be released by November this year.