When firefighters arrived at the scene of a construction trench collapse near Covington on Thursday afternoon, they could see two pairs of feet sticking out of the wet, sandy clay at the bottom of the 10-foot-deep trench.

But only one voice was calling for help.

The frantic rescue effort that followed, interrupted by safety concerns and bad weather, would bring one man safely to the surface. His co-worker did not survive.

Firefighters immediately jumped in and began trying to dig the men out from nearly a foot of dirt that had tumbled down on top of them from the sides of the trench, said David Windom, of St. Tammany Fire District No. 2.

But as the operation dragged on, they realized that being in the trench could compound the danger. The depth of the hole combined with the sandy clay made for a perilous work situation, Windom said. Moreover, huge piles of excavated dirt loomed over the side of the trench, adding to fears of another collapse.

The weather didn’t help. During the rescue, a rainstorm drenched the area and then was replaced by baking sun.

To lower the risk, firefighters had to delay rescue efforts while others brought in sheets of plywood to reinforce the sides of the trench. A ladder was laid across the top and another was lowered to the bottom. Firemen tossed water down to their comrades, and a large vacuum truck was brought in to suction out debris.

Two hours after the firefighters arrived, the surviving worker — stripped of his clothes except for a pair of blue and red striped shorts — was placed into a rescue basket and lifted slowly to the lip of the trench. He was immediately tended to by emergency medical technicians, who transferred him to a stretcher, where he was strapped down, his head immobilized and his arms folded over his chest.

The injured worker, who has not been named, was alert throughout the rescue and was able to speak with the men working to free him, officials said.

But there were fears that his medical condition could deteriorate quickly after he was pulled from the dirt. The weight of the soil could have been acting like a “big tourniquet,” said St. Tammany Coroner Charles Preston, an emergency physician. In that type of situation, he said, when the pressure caused by a heavy weight is removed, the flow of blood throughout an injured body can cause severe problems.

In this case, however, Preston said the worker was doing as well as could be expected, adding that his belly was soft, which indicated that the weight of the earth had not prevented his blood from flowing while he was buried.

Once the worker was taken away, the operation turned from rescue to recovery. The body of 24-year-old Isidro Cigarroa Martinez, of Baton Rouge, was taken out about 5 p.m., after more than four hours of being buried in the trench.

Lightning halted the recovery work at one point, said George Bonnett, of the Sheriff’s Office.

Questions about why the two men ended up trapped in the first place went unanswered on Thursday.

Sheriff Jack Strain, briefing reporters after the first worker had been removed, said his office would investigate whether all proper safety protocols had been followed at the site. Strain noted the presence of three trench boxes — large metal frames with two panel sides connected by thick bars — stacked just feet from where the collapse occurred but said there were none at the cave-in site itself.

“I don’t know why those weren’t in the ground, but those things will be looked into,” Strain said. State agencies may also investigate the incident, he said.

The trench was being dug to connect water and sewer service for a new building going up at the site, Strain said.

Follow Faimon A. Roberts III on Twitter, @faimon.