Loudoun County's appointed Planning Commission formally launched a process this week that could add tens of thousands of homes to the eastern part of the county.

The commission, disregarding the recommendations of the county's professional planning staff, agreed to accept for review eight of 10 development proposals they considered Monday. The commission will consider an additional 10 proposals next week.

The action sets in motion an undetermined period of analysis and leaves unsettled the question of whether proposals to change development plans near Dulles International Airport will be considered individually or as part of a planning effort covering a broader area.

In a coordinated bid to roll back county building limits, home builders and developers submitted 20 requests in recent months to allow the construction of tens of thousands of homes and millions of square feet of commercial space in what is already the nation's fastest-growing county. Even before those requests were made, builders had secured permission to increase the number of homes in the county -- about 83,000 -- by almost half. Existing plans would also allow tens of thousands more homes, county officials said.

The county's planning staff recommended that only three of the 20 development submissions be considered, arguing that many of the changes sought by applicants could be made without invoking the rarely used process to change the county's master plan. The proposals are known in county planning jargon as "applicant-initiated Comprehensive Plan amendments."

A central issue regarding the amendments is whether to increase the number of homes allowed per acre in the 23,000-acre "transition zone," which is between Loudoun's eastern suburbs and the more rural west. The transition zone stretches from Leesburg to south of Dulles and was the focus of most of the applications the commission agreed to review.

Planning Commission Chairman Larry Beerman (At Large) said that lopsided 8 to 1 votes on some of the proposals showed that commissioners were keen to learn more.

"We agreed we would hear more information," Beerman said. "This is just a starting point."

Beerman dismissed allegations from critics, including from Supervisor Jim G. Burton (I-Blue Ridge), that commissioners and members of the Board of Supervisors more sympathetic to stepped-up development were simply going through the motions of a public process when they had already decided they would allow substantial new development.

"I really have no idea what the outcome is going to be," Beerman said.

Commissioner John Herbert (Catoctin) said he voted against reviewing the proposals that would have resulted in increased housing densities near the airport because there was no guarantee that the overall impact of the changes would be considered.

"It's essential to look at them in conjunction with each other," Herbert said. That includes looking at the impact on roads and the environment, he said. Failing to consider overall effects "would be a great mistake and really dangerous for the county," Herbert said.

The proposals accepted for review were: One Loudoun Center, a proposal for a town center in the Ashburn area; the Criswell Co.'s proposal for a subdivision near Beaverdam Reservoir; and six large applications near the airport, including a proposal by Greenvest LC to build 15,000 units as part of the biggest residential development in the county's history.

The effects of the proposed changes could reach far beyond the thousands of acres covered by the submissions, said Planning Director Julie Pastor. New policies might apply to other landowners, and public spending to serve development could divert resources needed to serve current residents, she said.

"It affects the whole county," Pastor said.