On April 22, the Environment Protection Agency (EPA) submitted comments to the State Department on the draft supplemental environmental impact statement (SEIS). The comments focused on alternative pipeline routes, environmental justice impacts, greenhouse gas emissions, and pipeline safety. The agency expressed concern about the draft SEIS, advocating for further study on emissions, alternative routes, community impacts, and the risk of spills. The EPA recommended TransCanada put its pledge to conduct cleanup in writing. It warned that the tar sands transported in the pipeline could result in up to 935 million metric tons of additional carbon-equivalent emissions; it also warned that the revised route still cuts through the Ogallala Aquifer despite avoiding the Nebraska Sand Hills region. The comment period on the draft review began on March 1 and lasted for 45 days.