The Nuclear Regulatory Commission’s Three White Flint North office building in North Bethesda on Rockville Pike has only 373 employees working there. (Jonathan O'Connell)

The owner of Three White Flint North, a new 14-story office tower on Rockville Pike, proudly announced last week that the building had earned gold status under the LEED rating system for green buildings after achieving a 41 percent reduction in water usage, using locally sourced building materials and employing a green roof to absorb rainwater.

“We’re really, really pleased about that performance,” said Michael Smith, senior vice president and principal for the developer, LCOR.

But for all of its exterior environmental features, Three White Flint attracted far more attention last week for what’s inside it.

Which is not that much.

Despite the government having agreed to a nearly $350 million deal to lease the space in October 2009, the shimmering, 362,000-square-foot building — built specifically to accommodate growth at the Nuclear Regulatory Commission — is still mostly empty.

The revelation provided new ammunition for Republicans on the House transportation committee who have been conducting something of a traveling roadshow to highlight the need to sell off underused or completely empty federal buildings in the Washington area.

So far, they have held subcommittee hearings in the empty annex of the Old Post Office pavilion, the decommissioned West Heating Plant in Georgetown and a vacant warehouse near Nationals Park.

Three White Flint was spared that embarrassment during a House hearing last week. But Rep. Lou Barletta (R-Pa.), chairman of the subcommittee overseeing federal buildings, told how his staff toured the building on a Monday afternoon and found much of it vacant.

Committee staff even snapped a photo of a sign by the elevators saying NRC staff were not permitted on floors 5-12 of the 14-story building. This despite the government having invested $78.9 million in relocation costs and the building of an operations center in the building, as well as paying an average of more than $46,000 per day to lease the space.

The NRC, which oversees America’s 102 nuclear power plants, still occupies two buildings next door. But it says only about 373 people work in Three White Flint, a far cry from 2008 when agency leaders were so convinced that rising nuclear power production would require more staff and facilities that they bypassed the GSA and went directly to Congress to get the money appropriated for the lease.

D.C. Del. Eleanor Holmes Norton (D) said at the hearing last week that the move amounted to “playing with the taxpayers’ money.”

R. William Borchardt, executive director for operations at the NRC, acknowledged that the agency no longer needs all of Three White Flint. He testified that since signing the lease, the agency’s staff had not expanded as quickly as expected, as the number of new nuclear licenses tapered.

The NRC has since requested that it be allowed to extend an expiring lease at Two White Flint for another 20 years. Borchardt argued that certain facilities in the building, such as the Atomic Safety and Licensing Board Panel hearing room, would be expensive to relocate and suggested instead that parts of Three White Flint be offered to other federal agencies.

“Our suggestion, and I believe our best plan, is for us to retain White Flint Two and White Flint One in its entirety,” Borchardt said.

Barletta said that was a difficult case to make given that the agency has not occupied all of the new building next door when the president has asked agencies to “freeze the footprint” — or develop plans to restrict their growth.

“To sit through this and have federal agencies say they would prefer bigger space and would prefer spending more money to have nicer facilities and nicer space — well, I can tell you there are senior citizens that would prefer having heat.” Barletta said. “Mr. Borchardt, this is not acceptable.”