The National Boy Scout Jamboree (search) closed to visitors for a day of grieving and reviewing safety procedures Tuesday following the deaths of four adult scout leaders in an electrical accident. Three sons of the victims returned home to Alaska, officials said.

"Our hearts go out to the families of these dedicated Scout leaders who gave so much to their sons, their troops and their communities," Boy Scout spokesman Gregg Shields told reporters, his voice choked with emotion.

The accident happened Monday when the Scout leaders were setting up a dining tent. Officials said the gathering, which attracts tens of thousands of Scouts, would go on as planned. A memorial service was planned at Wednesday's opening ceremony.

One scout, Marty Williamson, 13, of Sparta, Wis., said Tuesday that he and his fellow scouts felt safe and "everyone is taking it pretty well."

Shields said the accident was under investigation and he could not provide additional details. Asked if a power line touched a tent pole, he said: "That's what we're investigating."

Rappahannock Electric Cooperative sent workers to the jamboree site to make sure it was safe, spokesman Brian Wolfe said. He said he was unaware of any problems with power lines before the deaths.

The victims were identified as Michael J. Shibe, 49, Mike Lacroix, 42, and Ronald H. Bitzer, 58, all of Anchorage, Alaska; and Scott Edward Powell, 57, of Perrysville, Ohio. Shibe had two sons at the Jamboree and Lacroix had one.

Three other adults were injured. One was listed Tuesday in critical condition at VCU Medical Center (search) in Richmond, one was in stable condition and another was discharged.

The youths with the Alaska troops — 80 Scouts ages 13 to 15 — were moved to an Army barracks where a chaplain and grief counselors were available.

Powell had lived in Alaska for 30 years and ran a Scout camp in Anchorage, but retired to Ohio about 18 months ago, said his sister, Anne Rentfrow, 49, of Mansfield, Ohio.

Powell had returned to Alaska this month to celebrate the camp's 50th anniversary. "While he was there, they invited him to go to the Jamboree," Rentfrow said. She said he accepted because he had never been to a jamboree.

"Last Wednesday, he was talking about some other project he was going to take on," Rentfrow said. When a relative commented he might be taking on too much, he answered, '"I've got a lot more 'yeses' ... I've got plenty of time."

Bitzer was a retired administrative judge and assistant scoutmaster of Troop 129 of Anchorage, according to troop Scoutmaster Ken Schoolcraft.

"Scouting was what he loved. He spent many, many, many hours working with Scouting," Schoolcraft said. "It was a way for him to help others."

The jamboree is being held on 3,000 acres of the Army's 76,000-acre Fort A.P. Hill about an hour south of Washington. Army officials are assisting with the investigation.

The jamboree runs through Aug. 3, with President Bush scheduled to speak Wednesday evening. The event, held every four years, attracts more than 40,000 Boy Scouts, leaders and volunteers from around the world.

The deaths came a day after a Boy Scout volunteer from North Carolina died at a hospital of an apparent heart attack.

The event has been held by the Boy Scouts of America (search) since 1937.

The next gathering is set for 2010, to coincide with the group's 100th anniversary, but it might not be held at Fort A.P. Hill, which has hosted the Jamboree since 1981. A federal judge recently ruled that the Pentagon can no longer financially support the event. If the ruling stands, the Boy Scouts would have to find another location for their next gathering.

A lawsuit filed by the American Civil Liberties Union of Illinois contends that the Defense Department's sponsorship violates the First Amendment because the Scouts require members to swear an oath of duty to God.

On Tuesday, the Senate took a step toward allowing U.S. military bases to continue to host Boy Scouts events. By 98-0, the Senate approved the measure in a provision that's part of a bill setting Defense Department policy for next year.

In exchange for getting use of the Army training base, the Scouts have spent about $20 million on base improvements that include road paving and plumbing upgrades. The Army says it uses the Jamboree as an opportunity to train personnel in crowd control, communications and other logistical skills.