OSO — Crews clearing mudslide debris from Highway 530 are making headway but the swift progress has come at a price.

Some workers have walked off the job, calling for the effort to slow down due to safety concerns and to allow them to better inspect the material for human remains and lost personal effects.

Crews have also discovered the force of the March 22 mudslide uprooted some 600 feet of the road.

The workers have been toiling around the clock in 12-hour shifts since the cleanup began earlier this month. So far, they’ve cleared roughly half of the 90,000* cubic yards of muddy debris that buried the highway. The mudslide left about 9,000 dump truck loads of debris on the road, said Travis Phelps, a spokesman for the state Department of Transportation.

Phelps said crews are on track to have the road cleared by the month’s end. The workers then plan to stabilize slopes along the highway for safety. They’ll also need to remove material that was left behind from the earlier search-and-recovery mission. At least 41 people died in the mudslide. Two remain missing and are presumed dead.

Once that work is complete, crews plan to determine what needs to happen before the highway can open to one-way, piloted traffic. Phelps said he expects drivers to be able to use the highway in a way similar to how the nearby power-line access road detour is currently operating. A fully rebuilt highway is expected to open to general traffic by October.

“We’ve made some significant progress over the weekend,” Phelps said on Monday during a visit to the site for reporters. “We’ve also been working in a very respectful manner.”

Some disagree with the way the work is being conducted. Several local people hired as spotters, who look through each scoop of dirt for human remains and personal items, walked off the job on Sunday. More quit on Monday.

Their main concern is for their safety. They also say the fast pace of the cleanup isn’t allowing them to do their job well.

Safety fears peaked during the lightning and heavy rain on Sunday night, said Rhonda Cook, one of the spotters who also worked in the debris fields during the recovery effort until it was suspended on April 28.

On Sunday, “I had people sinking up to their waist and their thighs trying to navigate their way,” Cook said.

The spotters are as eager as everyone else to see Highway 530 open because they know how important the road is to the local economy, particularly the lumber mills in Darrington, she said.

At the same time, they feel a responsibility to the families, particularly the two whose loved ones are still missing, to do the work right.

“We just all get a feeling we are being paid to do a job we just can’t do,” she said.

The walk-offs stopped work for several hours on Sunday and Monday, Phelps said.

The Transportation Department is working to address the concerns. Though hazards come with any construction site, Phelps said, he believes the workers are safe. He cited zero accidents or injuries since the cleanup started.

Crews continue to remove several hundred truckloads of debris out of the area each day.

The primary spotters are state archeologists who watch shovels when they break ground.

Local spotters then scan the excavated material as it’s poured into trucks.

The trucks haul the debris to a nearby dump, where more archaeologists look for recoverable items.

“That’s the balancing act of clearing the material and making sure we don’t miss anything,” said Bart Treece, another WSDOT spokesman.

Crews take care in sorting through the material because it’s important to return personal items of those lost in the disaster to their loved ones, Phelps said.

“It might be all they have left,” he said. “A lot of folks are looking for those types of things to come back to.”

So far, crews have recovered a smashed car and a Bible. No human remains have been located in the highway cleanup. Bodies are unlikely to be found near the road, according to analysis of the debris field.

Treece said there’s about 500 feet of buried highway left to go. Crews might find that more of the highway has been destroyed or displaced when they clear remaining mud. Workers have discovered yellow-striped chunks of displaced road.

“We’ve found some quite a ways away and some pretty close to where it’s supposed to be,” Phelps said.

WSDOT expects to award the final contract to rebuild the highway by month’s end. Phelps said four contractors are vying for the job, worth up to $30 million.

“We still have a lot of work to do,” he said.

Amy Nile: 425-339-3192; anile@heraldnet.com.

*Correction, May 21, 2014: This article originally included an incorrect figure for the quantity of the debris.