On July 10, 2020, the Maryland Department of Transportation (MDOT) released its more than 18,000-page Draft Environmental Impact Statement (DEIS) on the project, which addresses the construction project's impacts on people and the environment. If implemented, the highway expansion would fragment Plummers Island, which is located immediately downstream of the bridge. It would destroy or require relocation of the channel that separates the island from the mainland, clear-cut trees, and level a significant portion of the island. The native beech forest on the mainland side would also have to be cut down; wetlands between the mainland and the island would be destroyed, which can lead to a heavy infestation with invasive plants.[12][13]
In August 2022 the Federal Highway Administration approved the proposed project.[14] In October 2022 environmental and historic preservation groups filed suit against the state, citing deficiencies in the environmental review process and the projected impacts on Plummers Island.[15]
^Karl V. Krombein (1963). "Natural history of Plummers Island, Maryland". Proceedings of the Biological Society of Washington. Vol. 76. Biological Society of Washington. pp. 255–280.
^Timothy A. Pearce & Ryan Evans. 2008. Freshwater Mollusca of Plummers Island, Maryland. Bulletin of the Biological Society of Washington 15: 20-30.
^Stanwyn G. Shetler, Sylvia Stone Orli, Elizabeth F. Wells and Marcie Beyersdorfer. 2006. Checklist of the Vascular Plants of Plummers Island, Montgomery County, Maryland. Bulletin of the Biological Society of Washington 14: 1-57.