CEQA review is a process of investigation that is intended to disclose to decision makers and the public whether the project may have a substantial adverse effect on the environment. It neither denies nor approves a project; that’s the role of the public agency decision makers.
CEQA equates a substantial adverse effect on a historical resource with a significant effect on the environment. However, CEQA is a disclosure law, not a regulation. When an Environmental Impact Report (EIR) has been certified for a project, the decision makers may approve a project despite it having a significant, unavoidable impact on historical resources. Conversely, a project that may demolish or materially alter a historical resource cannot be approved on the basis of Negative Declaration or Mitigated Negative Declaration, an EIR must be prepared.