Dirt Cave-In Kills Laborer in Ditch in Mission Viejo : Accident: An engineer and geologist had just OKd the site. Co-workers could not dig victim out by hand.

A 42-year-old man working on a road extension in the hills here was killed Wednesday morning when a drainage ditch caved in, trapping him beneath a 10-foot mound of dirt.

The victim, Antonio Ramirez Diaz of Pacoima, was checking the bottom of a narrow ditch at the foot of a hillside on the Oso Parkway extension between Felipe Road and O’Neill Regional Park when one side gave way and buried him in the dark, clay-shale earth, said a distraught Cody Maresh of Orange, the backhoe driver working on the trench.

Just moments before the accident, everything appeared to be fine, Maresh said.

“He looked up at me and flashed the OK sign,” Maresh said. “Then, boom, it happened that fast. The dirt started at his legs and went right up over him. I’m 6-4, 280 pounds, and I felt helpless as a baby.”

Maresh and his fellow workers could hear Diaz’s cries for help, but their frantic efforts to dig him out by hand were unsuccessful.

“At first I couldn’t tell where he was because he was covered up,” Maresh said. “You could hear him, but the more dirt we pulled off, the more that kept coming in.”

Firefighters arrived minutes later, but it took them about 20 minutes to reach Diaz, said Kathleen Cha, spokeswoman for the Orange County Fire Department.

“He was buried pretty deep,” Cha said. “They got his head exposed and got him some airway, but he was unconscious and was pronounced dead on the scene.”

At the victim’s home in Pacoima in Los Angeles County, a relative said Diaz’s wife, Soccoro Diaz, was too grief-stricken to discuss the incident. The relative said Diaz had three children, a daughter age 17 and sons 13 and 7.

Wednesday’s accident was the second fatality in the last two months caused by a South County construction cave-in. A worker was killed April 8 in San Juan Capistrano after being lowered into a narrow trench to unfasten a chain from a piece of pipe.

Workers for Nelson & Belding, the Gardena-based subcontractors doing the roadwork Wednesday, said Diaz had been checking the grade at the bottom of the ditch before installing gravel and a 10-inch plastic drainage pipe. The hillside’s soil was known to be unstable, they said.

“We’ve dug 4 miles of this out here, and we know this ground is very unstable,” said Larry Brewer, a Nelson & Belding superintendent, pointing to visible cracks and slides on the surrounding hillsides. “What you can see you can run from. It’s what you can’t see that gets you.”

Brewer said an engineer and geologist had been on the site just before the accident and had given them the go-ahead to work.

The trench was being dug in stairstep fashion, as required by code, but the adjacent hillside caved in, Brewer said.

“Everything was cut the way the engineer wanted it,” Brewer said. “You can’t be safer than that. We just had a geologist down here.”

County Fire Department Battalion Chief Patrick E. McIntosh, who was at the scene, said the heavy clay-shale can be dangerous.

“The soil is the clay type that gets into a formation and very easily breaks away,” McIntosh said.

The Oso Parkway extension project is part of the Foothill Circulation Phasing Plan, a joint venture between area developers and the county to improve South County roads. The project will eventually link Oso Parkway with Antonio Parkway in Coto de Caza to provide a new route to that community.

Damp soil conditions occurring naturally in the area have already delayed completion of the extension, county officials said.

Much of South County was under water in prehistoric times. The deposit of tiny, fossil-like creatures has created a loamy soil condition that “holds water like a sponge,” said David Marshall, a county engineering supervisor.

“There is a high moisture content in the soil out there that has made it more difficult for us to complete this project,” he said.

Marshall would not speculate, however, on whether the damp earth contributed to the accident.

James Brown, district manager for Cal/OSHA, the state’s job safety agency, said an inspector was on the scene Wednesday and will file a report on the accident.

“We check to see if they are using the appropriate safety methods, that’s the main thing,” he said. “Then we look at the company’s safety program and record in general.”

Brewer and Bill Scott, another superintendent, said Diaz was a laborer and 12-year employee of the company.

Cave-ins are part of the hazards of any road-building job, Scott said.

“This just happened so fast,” he said. “We try to do everything we can, but these things happen.”

Times correspondent Frank Messina contributed to this story.