Only three of 21 requests filed by developers meet the criteria for changing the Comprehensive Plan governing what can be built where in the county, the Loudoun Planning Commission staff said.

The proposals were filed under a seldom-used process that allows landowners and developers to seek changes in the countywide development blueprint under certain conditions, such as if land-use circumstances have changed significantly or if they think they have an idea that would augment the county's land-use vision.

In all, the proposals envisioned tens of thousands of new homes and millions of square feet of commercial projects on 10,000 acres across the county.

Most of the biggest projects got thumbs down from the planning staff, including one from Vienna-based Greenvest LC, which applied to build 15,000 homes as part of the biggest residential development in the county's history.

Planning Director Julie Pastor said only three proposals met the criteria and should go forward for further review and public hearings. She said, however, that the Planning Commission can proceed with any of the other 18 projects if commissioners believe the criteria have been met or they think the development plan is a good idea and the criteria have not been met.

"Our assessments are basically focused on the criteria. It's not focused on the merits of the proposal," she said.

One proposal the staff said met the criteria was the Diamond Lakes project, a town center consisting of offices, homes, hotels, restaurants and other businesses, whose centerpiece was to have been a Major League Baseball stadium. When the Montreal Expos franchise was awarded to Washington instead of to Northern Virginia, Laurence E. Bensignor, a trustee of Van Metre Cos., said his development group would proceed with plans to build the 87-acre project beside Dulles International Airport at Route 28 and the Dulles Toll Road.

Pastor said county staff felt that an urban center near a Metro stop, as proposed by Diamond Lakes, could help realize the goals of the county's planning documents, even if it required amending their language.

The planning staff recommended expanding the area under study to include the entire quadrant north of the Dulles Toll Road, east of Route 28, south of Route 606 and west of the Fairfax County line "to allow for a broader planning process inclusive of the larger area."

The other applications planning staff recommended for further study were:

* A proposal by Salvatore Cangiano to build Stonegate, 406 single-family houses on 101 acres near Ashburn Village on land mostly zoned for an industrial park. The staff noted in its report that the Planning Commission had already agreed to review a Comprehensive Plan amendment to allow age-restricted retirement housing on adjacent property.

* A proposal by Washington Homes Inc. to build Victoria Station, a high-density housing development on 15.89 acres now zoned for an industrial park in Sterling adjacent to the existing residential neighborhoods of Tall Oaks and Peace Plantation. The developer wants to build 150 multifamily units.

"The Property is a perfect example of a zoned industrial tract that is not particularly well-suited for industrial development and, if so developed, would be an intrusion and potential nuisance to the existing residential neighborhoods," the Planning Commission staff wrote. "The Revised General Plan encourages the development of compact, mixed-use developments that provide people with the opportunity to live, work, recreate, and shop in a pedestrian-friendly environment."

In addition to Greenvest, proposals judged by the planning staff to not have met the criteria included those submitted by Virginia developer Randolph D. Rouse, who sought to build 3,000 homes.

The Planning Commission has scheduled meetings for Oct. 25 and Nov. 1 to review the staff recommendations. A final decision on any changes to the Comprehensive Plan rests with the Board of Supervisors, whose Republican majority was elected last year with the help of unprecedented campaign spending by real estate and development interests.