The Fairfax County Board of Supervisors, reacting to concern about the growing number of former county employes working for developers, adopted an ethics policy yesterday designed to curtail the potential for abuses in the county's regulation of the development industry.

The policy, approved by a unanimous vote, seeks to discourage employes who leave the county government for jobs in private industry from using their government contacts and information to benefit their new employers.

Although it carries no penalty, the policy imposes a one-year prohibition on former employes and county board members from reestablishing contact with county officials on projects in which they had "personally and substantially" participated.

The supervisors, in an attempt to make the measure legally binding, voted to ask the Virginia General Assembly to pass legislation this year authorizing them to adopt it as county law.

"This sends a message to developers and to our employes that these kinds of activities will not be tolerated," Supervisor Audrey Moore (D-Annandale), a leading advocate of the measure, said after its adoption. "We don't want people using the information they gained with the county for the benefit of a particular developer."

The board's action on employe ethics came moments after Board Chairman John F. Herrity denied allegations that he intentionally violated state and county public disclosure laws. Details on Page B1.

Herrity assumed partial responsibility for having "inadvertently overlooked" the names of some campaign contributors before participating in decisions involving their projects, but he blamed developers for failing to disclose their relationships with him on affidavits they are required to submit with zoning applications.

Several supervisors remained openly skeptical about the conflict-of-interest measure and its long-term implications on the county's ability to attract qualified employes. The county administration is "going to have trouble getting people to come here to work," said Supervisor Elaine N. McConnell (R-Springfield).

McConnell said the board will be better able to assess the impact of yesterday's decision "in about six months."

Fairfax officials who have resisted past efforts to enact such a law have contended that they need state approval beforehand. Moore said she hoped that the state legislature would take up the issue when it meets in special session in September to discuss transportation problems.

Similar ethics laws are in place in Montgomery and Prince George's counties, as well as in the District, which is covered by the U.S. criminal code.

The Fairfax board's decision came three weeks after a report in The Washington Post that cited the growing number of senior-level county employes who have left government positions for jobs with developers and consulting firms.

The article reported that several of the departing county staff members accepted private industry jobs soon after overseeing a major development project and that in some cases they were working on those projects for their new employers.

That practice has been sharply Similar ethics laws are in place in Montgomery and Prince George's counties as well as the District. criticized by some supervisors and Fairfax County Planning Commission members who contend that it creates the potential for serious abuses in planning and zoning decisions.

At the least, these officials have maintained, the rapid turnover erodes public confidence in the county's decisions on major development projects.

Despite persistent public pressure, the board rejected almost identical "revolving door" proposals several times in the late 1970s and early 1980s.

Lilla Richards, a prominent civic activist who has been in the forefront of attempts to bring about ethics reform, said yesterday that the board's action had been "long overdue." She said the supervisors had little choice but to adopt it this year because of the recent publicity.

"They are unable to avoid doing something about it now," she said.

Richards described the frequent job-switching by county planning staff members as a "longtime scandal," saying that "there has been too close of a relationship" between those staff members and developers.

Supervisor Nancy K. Falck (R-Dranesville), who had expressed reservations about the proposed ethics policy, said after yesterday's vote that the guidelines should serve as a reminder to employes, as well as the supervisors themselves, that "we expect proper behavior. I think most people that are employed by the county will agree that it is appropriate."

In addition to approving the policy for employes, the supervisors voted to urge county panels, authorities, commissions, agencies and task forces to enact identical policies for any of their members and employes who are paid by the county.