An article in Wednesday's Business section stated incorrectly that a proposed land-use change for 98 acres on the north side of Leesburg Pike in Fairfax included town houses. The proposal, by NV Land Co., calls for commercial development only.

Fairfax County's land-use master plan, the blueprint for development, is facing an unprecedented wave of challenges as developers hungry to build more office space and town houses attempt to cross many of the boundaries that have protected the county's stable residential neighborhoods.

The proposed changes, if approved, would mark the evolution of Fairfax County from a traditional bedroom community of single-family detached homes to an urbanized county -- fat with jobs and high-density housing developments -- as well as set the stage for further explosive growth into the next century.

Residents, many of whom moved to Fairfax in the last two decades seeking escape from urban pressures, have turned out in record numbers to oppose the plan changes. At the same time, others have abandoned any hope of reversing the trend and are offering their entire neighborhoods for office development.

Developers and landowners have proposed 300 changes to the plan, three times the number proposed during the last triennial review in 1982. County planners say that, were the proposals, which cover more than 10,000 acres, approved, they would allow 30 million additional square feet of office space, more than currently exists in Pittsburgh. In addition, the amendments would allow 18,000 more town houses than permitted under the current zoning, more housing than Reston has today.

"This is the year of commercial development," said William J. Keefe of the county's Office of Comprehensive Planning. "The development community is feeling its economic oats, and the developers are doing a nice job of taking their repressed financial wishes and putting them on paper."

Keefe, whose office staff -- along with other county staff -- has put in 2,000 hours of overtime struggling to assess the impact of each proposal, said that 30 million additional square feet of office space would be equivalent to two more Tysons Corners.

While each proposal affects only a single tract, their net effect would be to allow high-density town-house development in many established single-family neighborhoods, expand the boundaries of the booming commercial areas and permit development in environmentally critical areas.

Some of the major proposed changes to the comprehensive plan would:

* Expand the commercial development at Tysons Corner north of the Dulles Airport Access Road -- the traditional boundary -- into an area of single-family homes by allowing 98 acres of mixed low-rise office and town-house development between the access road, Route 7 and Lewinsville Road.

* Turn the 3,000-acre Lorton prison facility into a mixed-use residential and commercial development.

* Increase the housing density 20 times on an 817-acre tract along Pleasant Valley Road in the environmentally fragile Occoquan watershed.

* Allow a 273-acre retail, office and residential development at the intersection of Route 7 and Baron Cameron Road, the main artery into Reston.

* Create a commercial development of 4.5 million square feet of office space at the intersection of Hunter Mill Road and the Dulles access road. Reconsider the plan for the entire Oakton area, including a proposal to extend Hunter Mill Drive to link up with Blake Lane, which would create a direct commuter corridor from Reston through congested Oakton to the Vienna Metrorail stop.

* Reconsider the plan for the entire southeastern sector of the county, from Springfield and the I-95 corridor east to the Potomac River, an area of almost 40 square miles.

* Allow more than 1,000 acres in the 5,000-acre Fairfax Center area to be changed from residential use to commercial, despite current zoning allowances for up to 13 million square feet of office space in the area.

* Allow 6 million square feet of light industrial and office space on 350 acres in the Centreville area.

The current comprehensive plan, drawn in 1975, outlines general land-use patterns for the county. Amendments to the plan are considered every three years and, if justified by the changing development of the county, may be approved by the Fairfax County Planning Commission and forwarded to the Board of Supervisors for final action.

Although the county always gets some land-use amendments, a member of the planning staff said that this year "everybody seems to be asking for changes," including neighborhood associations seeking to have their subdivisions rezoned for commercial uses so their members can sell their land at premium rates and escape the county's noise and congestion.

According to a staff summary, there are proposals to build town houses "on excess graveyard property and . . . almost everywhere else in the county," including a number of proposals to allow "in-fill development" of town houses in single-family neighborhoods such as McLean, Great Falls and the Bailey's Crossroads area. "In-fill development" refers to building that increases the density of existing neighborhoods.

In addition to the major proposals listed earlier, there are several amendments that would allow for new hotels, five proposals for housing for the elderly, and a plan to expand the high-rise commercial development in the central business district of McLean north to Dolley Madison Road and to the south in the area behind the Gourmet Giant supermarket.

"A lot of the [proposed amendments] challenge the viability of the development centers even though those centers are not built out yet," said Keefe of the planning office. "We'd like to see the commercial cores reinforced rather than dispersed."

If all the proposals were approved, the resulting high-density residential and commercial construction could have a severe impact on the county's burdened transportation system and strain other support services such as schools and fire and safety facilities, the county planning staff said.

In fact, the planning staff has recommended that most of the proposals be denied or curtailed substantially. Because some of the 300 proposals have been consolidated, there are only 224 before the planning commission. The staff has recommended denial of 76 and suggested significant changes for 52. Applicants have withdrawn 11, including the Route 7-Baron Cameron proposal and the Hunter Mill Road-Dulles access road proposal. But those two are expected to be resubmitted.

The staff has recommended denials of most of the in-fill town-house developments, saying that residential growth should be encouraged only in areas already targeted to accommodate more housing, such as Herndon, Reston, Vienna, Centreville and Fairfax Center.

Of those remaining, 56 have been deferred until additional studies can be done, including studies on the Fairfax Center area, a retail study of the Route 50 corridor, a study of the Merrifield area (Route 50 and the Beltway), and a study of the Centreville area and the land surrounding the proposed Center for Innovative Technology near Dulles Airport.

Proposals for areas around the county's Metrorail stations also have been deferred until citizen task forces complete recommendations for development at each station site.

Only 33 of the 224 proposals have been recommended for approval.

Planning commission hearings on the proposals during the past three weeks have attracted standing-room-only crowds as community groups registered complaints or promoted their own proposals.

Developers defended many of the residential building plans by saying that the new Dulles toll road and yet-to-be-built Springfield bypass had generated more transportation capacity. They also said that the county simply needs more houses, from expensive homes for top executives to affordable housing for the growing number of people moving to the county as part of the continuing commercial and retail boom.

Planning commission member Rosemarie Annunziata, however, repeatedly asked developers to explain the land-use rationale for their required changes.

Far too often, the rationale is simply that "you want it," Annunziata told one applicant.

The planning commission is expected to begin considering the proposals tonight. Those surviving that process will be acted on by the Board of Supervisors in early summer.