The Advisory Council on Historic Preservation (ACHP) is seeking comment on a proposed Program Comment submitted by the FCC regarding collocation on twilight towers. Twilight towers are those towers constructed between the adoption of the 2001 collocation nationwide programmatic agreement (NPA) and the effective date of the 2005 wireless facilities NPA, without undergoing Section 106 historic preservation review. The FCC wants to establish a process for considering the effects of collocations on twilight towers. Currently, telecommunications carriers will not collocate on these towers because the Section 106 process was never completed for the original tower construction. Resolution of the issue would allow for collocations on thousands of towers. The ACHP has 45 days to review the Program Comment and decide whether to approve. Comments are due by September 25, 2020; however, the National Association of Tribal Historic Preservation Officers has requested an extension for comments. In 2017, the FCC attempted to resolve the twilight tower issue but was met with opposition from tribes and state historic preservation officers.