The regional airport authority voted yesterday to condemn and take over the site of a planned mid-rise office building about 1,500 feet from the end of one of National Airport's primary runways, citing safety concerns.

The Federal Aviation Administration considers the proposed five-story building, near the George Washington Memorial Parkway and Shirley Highway, a potential obstruction but not a severe hazard to air traffic. Arlington County had granted a construction permit for the building.

The property is in a "clear zone" for aircraft approaching runway 15/33 at National Airport, which handled nearly 16 million passengers last year. Many tall buildings exist west of the airport terminals, in Crystal City, but those are not in designated clear zones, where the FAA discourages development.

The planned building would be 56 feet tall, or 74 feet above sea level, according to Arlington zoning officials. It would provide almost 80,000 square feet of office space on what now is a parking lot.

The safety concern is based on "the height coupled with the fact that this would be a lot of people" working close to the runway's edge, James Wilding, general manager of the Metropolitan Washington Airports Authority, said after yesterday's vote. There are no other similar buildings in clear zones at National or Dulles International Airport, he said.

The FAA had told the property owners and Arlington officials that the proposed building fell short of the definition of a serious hazard but still was undesirable, according to Anthony Spera of the FAA's eastern region.

Arlington officials "really didn't have any justification" to deny a building permit for the site because the land is zoned for offices and the FAA didn't formally declare the proposed building a serious hazard, said county Zoning Administrator Susan Ingraham.

Airport officials said representatives of some airlines had also expressed concern about the building. Officials said they are negotiating possible sales or use limits with owners of about 22 other nearby acres to keep the runway approach zone as safe as possible.

John Kyle, an owner of the property, said he and his partners will not challenge the condemnation. "We would love to have built the building a year ago," Kyle said, but "there was a cloud over our head" because of safety concerns.

The most recent assessment for the parcel, which is slightly more than one acre, is $1.2 million. Neither the airport authority nor the owners would speculate on the price that the agency would have to pay to obtain the land through the courts. The airport agency has the power under Virginia law to acquire land for the public interest.

Negotiations between the parties on a direct sale have not succeeded, officials said yesterday. Officials did not discuss how the agency would use the land.

Under legislation governing the airport authority, the Congressional Review Board has 30 days to exercise its veto power over major authority actions, including the condemnation. But that legislation is under review by the Supreme Court after a lower court ruled that the Board of Review is unconstitutional.

Also yesterday, the airport authority delayed action on a measure that would allow the private, for-profit Toll Road Corp. of Virginia to cross Dulles International Airport property with its extension of the Dulles Toll Road to Leesburg.