The National Historic Preservation Act (NHPA) and the National Environmental Policy Act (NEPA) are two separate laws which require federal agencies to “stop, look, and listen” before making decisions that impact historic properties and the human environment.
NHPA was signed into law in 1966, and Section 106 of the NHPA requires federal agencies to take into account the effect of undertakings they carry out, license, approve, or fund on historic properties and provide the Advisory Council on Historic Preservation (ACHP) a reasonable opportunity to comment before making decisions. Using the Section 106 process, agencies identify historic properties, assess effects to historic properties, consider alternatives to avoid, minimize, or mitigate any adverse effects, and document their resolution. Agencies are required to facilitate a stakeholder engagement process known as consultation – discussing and considering the views of consulting parties, including State Historic Preservation Officers (SHPOs) and/or Tribal Historic Preservation Officers (THPOs), Indian tribes, Native Hawaiian organizations, and others, while also providing opportunities for public input. The ACHP, an independent federal agency established by the NHPA, oversees the implementation of the Section 106 process, issues its implementing regulations (36 CFR Part 800), and may participate in consultation to resolve adverse effects to historic properties.
NEPA was signed into law in 1970 and requires federal agencies to assess whether a major federal action has the potential to significantly affect the human environment prior to making decisions. Using the NEPA process, agencies evaluate the environmental and related social and economic effects of their proposed actions. This is done through preparation of an Environmental Assessment or an Environmental Impact Statement. NEPA is often described as an “umbrella” law as its analysis incorporates a broad range of federal laws, regulations, and executive orders. Under NEPA, agencies are required to provide opportunities for public review and comment, so the agency may consider those comments. NEPA established the President's Council on Environmental Quality (CEQ) to oversee NEPA implementation. CEQ has issued regulations (40 CFR Parts 1500-1508) to implement NEPA.
NEPA and Section 106 are separate requirements with different parameters for what is afforded consideration in each review. Section 106 review concerns effects only to historic properties, while NEPA encompasses consideration of impacts to a wider range of resources within the human environment, including historic properties and other cultural resources among many other elements.
Federal agencies’ statutory obligations under NEPA and NHPA are independent, but integrating the processes creates efficiencies, promotes transparency and accountability, and supports a broad discussion of effects to the human environment. CEQ and the ACHP developed a Handbook to promote better integration of the two review processes, and ACHP offers e-learning courses on the Basics of NEPA and Section 106 Integration and Coordinating NEPA and Section 106.
Section 106 review must be complete prior to issuance of a federal decision, so that a broad range of alternatives may be considered during the planning process. Because the information gathering and consultation done in the Section 106 review should inform the NEPA review, and vice versa, the timing of both reviews should be coordinated. For example, a finding of adverse effect under Section 106 may help determine whether “extraordinary circumstances” exist that would prevent an agency from utilizing a categorical exclusion from NEPA for a particular action.
Integration of NEPA and Section 106 should begin early, to enhance agency planning. Integration of NEPA and Section 106 makes sense because: the historic properties of concern in Section 106 are one type of resource in the human environment considered in NEPA; both processes are triggered by federal funding, permits, licenses, or other approvals and share goals of providing transparency and allowing for public involvement; both processes should be initiated early in project planning when a broad range of alternatives can be considered; and, completion of both processes is needed for agencies to proceed to implement an action or undertaking. In addition, agencies are encouraged to combine public involvement efforts for the two reviews to avoid duplication of effort and to maximize opportunities for public and consulting party involvement.
The ACHP-CEQ Handbook includes flowcharts to clarify timing and communication touchstones for Section 106 with NEPA. The Handbook also includes guidance to help agencies substitute the NEPA process for Section 106 through a procedure specified in the Section 106 regulations (36 CFR § 800.8(c)).
CEQ is in the process of revising the 2020 NEPA regulations. The Phase 1 final rule, effective May 20, 2022, among other things, amends the definition of “effects or impacts” at 40 CFR 1508.1. While the relationship between NEPA and Section 106 reviews remains fundamentally the same, the frequent coordination of the two review processes warrants ensuring that the Handbook is updated to reflect new citations and current terminology. This updated Environmental Impact Statement (EIS)-Section 106 flow chart with current citations serves as a supplement to the Handbook illustrating how the two reviews align.
This chart provides updated definitions of key Section 106 and NEPA terms referenced in the Handbook.