A laborer was electrocuted and another injured yesterday morning in a Loudoun County construction accident involving a crane and high-power electrical lines.

Joseph P. Brown, 37, of Front Royal was electrocuted as he helped tie down a bundle of construction equipment that was to be moved by crane to a flatbed truck. He was pronounced dead on arrival at Fairfax Access hospital at Reston.

James Sealock, 51, also of Front Royal, was injured as he helped Brown. He was admitted to Fairfax Hospital yesterday afternoon and listed in good condition.

Don Dohallow, project engineer for Peter Kiewit Sons Co., said the accident occurred when a high-voltage current arced from power lines to the boom of the crane loading the equipment.

"Somehow it [the voltage] must have jumped across. The crane operator said he didn't touch the power line," Dehallow said.

Loudoun and Fairfax fire and rescue departments were unable to provide a more detailed account of the incident.

The accident occurred on Seneca Road near the Potomac River at the site of a nearly completed raw water pumping station built by the Kiewit firm for the Fairfax County Water Authority. The station will supply water for a new water purification plant located five miles away near Herndon.

Investigators from the U.S. Occupational Safety and Health Administration were at the accident scene yesterday. An OSHA spokesman said it will be at least several days before results of an investigation will be released.