A debate with few precedents in American historic preservation - what are the meaningful physical remnants of a place that was all but destroyed? - has turned into a confrontation between preservationists and state officials.
Yesterday, the National Trust for Historic Preservation called on the Lower Manhattan Development Corporation to let the keeper of the National Register of Historic Places determine which remnants of the World Trade Center deserved heightened scrutiny; for example, the severed cast-iron PATH tubes or the smoke-scarred ruins of an underground parking garage.
"Those smoke scars would be analogous to the strafing marks in the concrete at Pearl Harbor, which are considered highly significant physical remains from the 1941 attack," Elizabeth S. Merritt and Marilyn Fenollosa of the trust wrote in a letter criticizing the development corporation's findings. "Yet these smoke scars appear to be dismissed as lacking in significance without any analysis whatsoever."
No one doubts the significance of ground zero. But a complex federal review process is revealing stark differences of opinion over which remnants, if any, contribute to the historical resonance of the site. How these elements are treated may, in turn, affect the design of the new buildings that are to rise there.
On Feb. 6, the development corporation said the entire site would be eligible for listing on the national register. But three days later, it issued a document saying the "significance of the transcending events of Sept. 11 and the aftermath clearly does not depend on the presence of the original, or even the damaged, buildings and structures" and made a preliminary determination that redevelopment would have no adverse effect on any historical features.
Faulting both documents, the trust, an influential nonprofit organization, has joined the New York Landmarks Conservancy, the Municipal Art Society, the World Monuments Fund and the Preservation League of New York State in identifying the garage ruins, the slurry walls, the sheared-off steel column footings from the towers and a staircase and escalator structure on Vesey Street as "features that clearly contribute to the significance of the site."
They called on officials to consider artifacts removed from the site in assessing its historical significance.
Irene Chang, the vice president for legal affairs and counsel to the development corporation, said the agency was committed to keeping parts of the slurry wall visible, allowing access to the column footings and preserving the tower footprints as voids.
"In our view," she said, "the plan recognizes and incorporates the most important elements. While there has been a flurry of letters and a discussion of the process, we really aren't that far apart in substance as to what's important to preserve."
Ms. Chang said that because the artifacts had all been removed, they could not now be used to assess the significance of the site itself. "If they were returned, they could contribute to the historic significance of the site," she said.
Eligibility for national register listing does not convey the protection found in local landmarks laws. And preservationists said they were not trying to freeze the site in time.
"We're certainly not taking the position that the remains of the parking garage have to be left intact," Ms. Merritt, the deputy general counsel of the trust, said in a telephone interview. "It's just that these types of features that have a connection with the attack have to be taken into account in planning how the memorial space goes forward."
She added, "The national register issues raised by this site are so unique that it would be appropriate for the keeper of the national register herself to look at the determination." A telephone message left late Friday afternoon at the office of the keeper of the register, Carol D. Shull, was not returned.
The review, governed by Section 106 of the National Historic Preservation Act, is overseen by the federal Advisory Council on Historic Preservation. Some preservationists have urged the council to assume a more forceful role in the trade center matter.
A spokesman, Bruce J. Milhans, said the council "will decide what action it will take after seeing how the L.M.D.C. responds to the comments they receive."