Fairfax County Board Chairman John F. Herrity, charged by the county prosecutor last week with violating the state ethics law, publicly questioned the accusation yesterday and then angrily walked out of a Board of Supervisors meeting.

Herrity left as the board was preparing to consider a rezoning application by the Fairfax County chapter of the American Red Cross. He said that as a member of that organization's board of directors, a nonpaying position, he planned to disqualify himself from the case.

That assessment of the situation was disputed by Supervisor Audrey Moore (D-Annandale), who said that Herrity's position with the Red Cross was a largely ceremonial, county-related function that had nothing to do with the state and county laws requiring public disclosure of financial relationships between developers and supervisors.

Herrity responded by noting that he was already the subject of one criminal charge under the state ethics law and said he did not plan to risk a second.

He said there had been no evidence that he benefited financially from his business relationship with Hersand Builders Inc.

That relationship is the subject of the charge against Herrity. He is accused of unlawfully failing to disclose that relationship when the developer appeared before the board on a major rezoning last winter.

Referring to his scheduled trial next month, Herrity said, "I've got to spend $25,000 to defend myself in court over there, so I'm getting out of here." He then left the meeting.

Herrity's departure came during a tense meeting at which he and other supervisors continued to show displeasure over the requirements of the public disclosure laws. The laws require board members, before participating in land-use cases, to disclose whether they have a business or financial relationship or have received a campaign contribution from anyone connected with the case.

Herrity is charged with failing to disclose that he owned a 25 percent share in an office condominium venture with the president of Hersand Builders Inc., Herbert L. Aman III, and Aman's wife Sandra as he and the rest of the board was reviewing Hersand's controversial town house project.

Some board members have complained that the disclosure laws are unclear and, in some cases, go too far. Moore, a longtime proponent of strict disclosure laws, has said that some board members, including Herrity, are trying to rescind or dilute the laws by making a mockery of them. She said yesterday that Herrity's abstention in the Red Cross rezoning case was an example of his trying to portray the law as impractical.

Herrity had not returned to the meeting an hour later as the board took up another rezoning application by Hersand.

In its latest application, Hersand was seeking the county's approval to add three acres and 14 town houses to the 41-acre, 124-unit town house development, which the board approved in February. With only five of the nine supervisors present for the debate, the board found itself unable to decide the controversial case and postponed a decision until next week.

The issue is a particularly sensitive one for Supervisor Elaine N. McConnell (R-Springfield), who represents the district in which the project is located.

McConnell, largely in response to a countywide citizen backlash against further development, has recently announced her opposition to plans that would grant developers density bonuses given in return for promised improvements or amenities such as open space.

Hersand officials contend that they have more than compensated for the increased density with their promise to provide public improvements at the development site.

Aman, Hersand's president, declined to respond to a reporter's questions about his project and the board's decision to delay it.