Assets of other external agencies could play a decisive factor in the evaluation of alternatives. It is recommended to consider the impacts of railroads, irrigation/water resource entities, navigable waterways (US Coast Guard-regulated waters), Environmental Protection Agency superfund sites and concentrated areas (e.g., abandoned underground storage tanks), and Federal Aviation Administration (FAA) airport vicinity restrictions. Significant utilities such as interstate pipelines, fiber optic backbones, and overhead transmission lines can be considered as well. Mitigating impacts for such complications can be a costly and lengthy process.