In March 2019, the D.C. circuit court issued an opinion that clarified the meaning of the term “directly” in Section 110(f) of the National Historic Preservation Act as referring to the causality, and not the physicality, of the effect to historic properties. This means that if the effect comes from the undertaking at the same time and place with no intervening cause, it is considered “direct” regardless of its specific type (e.g., whether it is visual, physical, auditory, etc.). “Indirect” effects to historic properties are those caused by the undertaking that are later in time or farther removed in distance but are still reasonably foreseeable.
This clear statement should assist federal agencies not only in determining when Section 110(f) may apply to an undertaking that is subject to review under Section 106 of the NHPA, but also how to characterize the types of effects that may be caused by an undertaking. For many, this will change the approach to defining effects based on physicality and recognize instances when direct effects may be visual, auditory, or atmospheric. This clarification should inform an agency’s efforts to determine areas of potential effects and consideration of how an undertaking may affect historic properties.