Sen. Thomas F. Eagleton (D-Mo.) has asked the National Capital Planning Commission to undertake a "complete investigation" of why NCPC members were not told in 1979 that the Secret Service believed developer Oliver T. Carr's new 12-story Metropolitan Square building posed a threat to White House security.

Eagleton, who represented the Senate on NCPC in 1979, said in a letter to the federal planning agency that it was "inexcusable" that members were not told of the Secret Service concern over the 148-foot structure at 15th and G streets NW.

The Secret Service reiterated its concern over Metropolitan Square last week, asking Mayor Marion Barry to delay issuing permits for construction of a planned 157-foot-tall second phase until the Secret Service and city officials resolve security questions about the building that overlooks the north portico of the White House.

"I would think that any building which allows direct visual access to the White House grounds should be prohibited," Eagleton wrote to NCPC chairman Glen T. Urquhart, "and I would think a return to the 1910 height limits in the area would be advisable." In 1979, the City Council--also unaware of the Secret Service concern--amended the 1910 height limit of 95 feet on 15th Street to allow Carr to build to a height of 130 feet (148 feet including a rooftop equipment house).

Yesterday, NCPC executive director Reginald W. Griffith, who had withheld mention of the Secret Service position from commission members in 1979, said he would welcome an investigation.

Griffith said in an interview last week that he did not inform NCPC members because the Secret Service had requested that he keep "a low profile" on the security issue, and because NCPC technically did not have jurisdiction over approving or denying height changes. Griffith also said he did not want to discuss it with then-chairman David M. Childs because Childs, an architect, designed Metropolitan Square for Carr and therefore would face a potential conflict of interest in considering the matter.

Eagleton, referring to recent press reports on the 1979 situation, said, "I do not buy any of the excuses reported thus far for not informing the commission."

NCPC is the federal government's central planning agency for the city and is supposed to represent "the federal interest" in zoning and planning matters. "If the security of the President of the United States is not within the 'federal interest' which the NCPC exists to protect, then what is?" Eagleton wrote.

Carr Company spokesman Michael McGowan said yesterday that the firm has met several times with the Secret Service in recent weeks, and "we are optimistic that all these concerns will be resolved adequately" for both the existing building and the second phase.