Arlington County Board member Charles P. Monroe (D) suffered a ruptured brain aneurysm yesterday during his first regular meeting as chairman and died a short time later. He was 46.

Monroe was responding to a resident's concern when he repeated a sentence, fell silent and then slumped to one side in his chair. Paramedics took him to Virginia Hospital Center-Arlington, where he was pronounced dead at 12:07 p.m.

Monroe, a lifelong Arlington resident and the son of Arlington's first black Circuit Court judge, was known as a keen listener and a quiet leader. He had served on the board since 1999, and fellow board members chose him as their chairman last month.

"He was one of the kindest, fairest people I think any of us ever met," said Vice Chairman Paul Ferguson (D). "He loved Arlington County, his job and his family. . . . He approached every issue with an open mind."

On New Year's Day, in accord with county tradition, Monroe laid out his agenda for his chairmanship, including creating a list of Arlington's 50 most dilapidated properties as a first step toward getting rid of them.

Monroe, a graduate of the Washington & Lee University School of Law, was a lawyer with Alexandria-based Duncan and Hopkins. Before joining the Arlington County Board, he was a civic activist and an advocate for the working poor. He had been active in several civic organizations and advisory groups, including the Arlington Human Rights Commission and the Arlington Housing Corp. board.

"Serving on the County Board for Charles was about service to the county, not for any personal political ambition," said Dan Steen, chairman of the Arlington Democratic Committee. "This is a shock to all of us. . . . He had plans to serve the county in so many ways."

Democratic Committee officials said county rules call for a special election to fill Monroe's seat, which will be up for election for a full four-year term in November. Arlington's last special election was in 1999, when Albert C. Eisenberg stepped down to work for the Clinton administration.

Monroe was speaking from the dais about 9:20 a.m. when he collapsed. Board member Barbara A. Favola (D), sitting next to him, immediately leaned over to check on him and asked for help. Paramedics responded within a few minutes.

County staff members and residents attending the County Board meeting were visibly shaken as they congregated in the lobby outside the board chambers on Clarendon Boulevard while paramedics attended to the chairman. Four clasped hands and prayed, while others talked softly among themselves.

"We were really looking forward to working with him because he listened to his constituents, and all of us were excited about his leadership style," said Dan Krasnegor, president of the Arlington Civic Federation, an umbrella group of the county's civic organizations.

Monroe, who grew up in the Nauck community and lived in South Arlington, is survived by his wife, Barbara, and their sons, Christopher and Jonathan.

Charles P. Monroe was a lifelong Arlington resident and longtime activist before his 1999 election.