[2] In that same year, Allegheny Energy introduced a passive treatment system where groundwater from the fly ash landfill is treated with wetlands.

[4] Allegheny Energy commissioned a flue-gas desulfurization (FGD) system, designed by Babcock & Wilcox, to be installed at Hatfield's Ferry in 2006.

[5][6] The equipment, which cost $700 million to install, removed 95% of sulfur dioxide (SO2) and lowered mercury emissions at the plant when it was activated in 2009.

The company decided against investing $245 million to retrofit Hatfield's Ferry in order to comply with the Environmental Protection Agency's (EPA) Mercury and Air Toxics Standards (MATS).

[7] In 2018 APV Renaissance received the final environmental permit[8] required to break ground on a new 1,000-megawatt natural gas power plant on the site of the former coal pile.