The Army Corps of Engineers said it will begin its search in March for old military explosives along a proposed bike path in Rancho Santa Margarita's O'Neill Regional Park.
The sweep for unexploded ordnance at the former bombing range had been scheduled for 2023 but was quickly advanced with the discovery two months ago of 11 small bombs under about a foot of soil by workers preparing to lay asphalt for a bike path in the park.
Clearing the 3,200-foot, 20-foot-wide path is expected to take about two weeks, said Corps spokesman Greg Fuderer. It is unclear when the remainder of the 1,800-acre wilderness park will be cleared of explosives, he said.
The park is within the Plano Trabuco bombing range, used by Navy pilots from the former El Toro base from 1944 to 1956. Officials don't know how many unexploded practice bombs may be scattered across the site.
"The immediate concern was the bike path area, a heavily traveled trail, and that's being taken care of," said Rancho Santa Margarita Mayor Gary Thompson. "The rest of park does represent a continuing danger to the public because it's not fenced and it is accessible. Still, it's much less of a danger than the trail."
Signs along the path warn hikers and bikers of the bomb danger, and a buffer zone will be created once the sweeping begins, Fuderer said.
The Defense Department has estimated that 1,030 former military sites are now in private or public ownership, and at least 620 of them are believed to contain unexploded ordnance.
The Army Corps of Engineers, the federal agency overseeing the former Trabuco Bombing Range, focuses on cleaning up the most dangerous sites. The corps gave Trabuco the second-highest of five priority levels, qualifying it for cleanup in 2023.
But the September discoveries and pressure from Rep. Gary Miller (R-Diamond Bar), whose district includes Rancho Santa Margarita, moved up that timetable, at least for the bike path. Officials say other ordnance in the park would be buried at least a foot deep and would not pose imminent danger.
Kevin McKee, a Miller spokesman, said the congressman is working to get the entire park cleared. "It will take an act of Congress to move up the date because of the high costs of cleanup," McKee said. "We're trying to get the cleanup of the park included in a bill."
Even before workers found the three groups of military bombs over a 28-hour period in late September, the old bombing range was scheduled to be reevaluated in 2004.
"We'll go in next year and take another score," Fuderer said. "Because of the growth of the area, the number of bomb sightings and interest from the Department of Toxic Substance Control, we needed to take another look at this site."
In 2001, a sweep of the entire park was estimated to cost $2.7 million. The Corps said combing for bombs along the bike path will cost about $270,000. The Corps said round-the-clock guards will be on duty once cleanup begins.
Fuderer said the Alabama-based contractor performing the cleanup hasn't determined a method of disposal for explosives. "They will either blow them up on-site or move them elsewhere and then detonate them," he said.