Last Stand for WWII Bunker : Development: The 600-by-175-foot structure, built in 1944 to defend area against Japanese, was a familiar landmark. Demolition will take 6 months, clear way for new homes.

Battering rams began chipping away at a historic World War II bunker near the Bolsa Chica wetlands on Tuesday, initiating the final phase of the structure’s demolition to make way for thousands of new homes.

Beginning at 7:45 a.m., a 14,000-pound hydraulic hammer mounted on a caterpillar began pulverizing the structure’s thick concrete walls, built to withstand air raids, punching them in staccato ear-shattering bursts that exposed tangled steel reinforcements and filled the air with dust.

“I’m glad to get the process going,” said Lucy Dunn, senior vice president of the Koll Real Estate Group that wants to build 3,300 houses near the site. “This is a great . . . nuisance; the sooner we get this done, the better.”

Bob Williams, a spokesman for the Sierra Club, which had joined with other groups to save the structure by arguing that its demolition would damage nearby bird habitats and Native American archeological sites, had a different view.

“I’m sad that the developers are putting their bottom line in front of the heritage of the citizens of this area,” he said. “I think it’s a loss for Orange County and for World War II veterans. It’s the loss of another bit of history for our children (who need) visual reminders of the costs of war.”

The 600-by-175-foot concrete bunker, long a local landmark familiar to hikers, bicyclists and youthful graffiti artists, was built in 1944 by the U.S. Army Corps of Engineers as part of an elaborate coastal defense system aimed at protecting California from attack by the Japanese.

The bunker, designed to hold gun emplacements at either end protected by 16-foot-thick ceilings and six-foot-thick walls, contained huge storage areas for ammunition, as well as latrines and sleeping quarters for its crew.

Before the facility could be armed and the finishing touches applied, the war ended. Last year, the National Park Service declared the bunker eligible for listing on the National Register of Historic Places.

And recently it has become the focal point of an intense debate between those who would preserve the structure for its historical significance, and the Koll Real Estate Group.

Last week, a Superior Court judge ended the argument by siding with the Koll company, thus clearing the way for demolition. And this week, assuring preservationists that the structure’s historical significance would be documented in videos and photographs, the company began its incessant pounding.

“It’s going to be a (tough) job,” operating engineer Steve Stapleton said of the demolition, expected to take about six months and cost more than $1 million. “This old concrete is harder” than the new stuff.

Across a vacant field in the adjacent neighborhood where the sound of Stapleton’s mechanical battering ram could be heard as a distant rat-a-tat-tat, residents were reacting with sadness and concern.

“I think it should be saved,” resident Susan Hatch said of the familiar ghostlike structure. “How many bunkers do you see from World War II?”