On May 9, AES Corp. filed documents with the Securities and Exchange Commission, announcing the April 2016 closure of 620 megawatts worth of coal-fired power plants in the Midwest. The company cited strict Environmental Protection Agency mercury and air toxic standards as the reason for the plants’ closure. It also announced the plan to convert two units at a facility near Indianapolis to natural gas; another proposal was submitted to construct a new natural gas-fired plant.