An 11-year-old boy says he was trying to protect his three playmates from lightning when he led them to the shelter of an embankment. It collapsed on them and killed his friends.

"I thought it was my fault," said Mitchell Bass, who survived with bruises. "I felt guilty like I had killed them."I was just trying to get the girls to safety," he said Monday. "If I had known that would happen . . . "

Mallory Bush, 11, and her 10-year-old twin sisters, Jessica and Jillian, died while trapped beneath dirt and boulders for about 45 minutes on Sunday.

The girls had been spending the weekend with their father, Danny Bush, who lives with Mitchell's mother, Cheryl Bass.

On Sunday, the four children were playing at a clay pit when a storm began.

"Lightning was popping all around us," and they gathered beneath the overhanging embankment, Mitchell said. He heard a car approaching and stepped out to see if it was his mother, and seconds later the overhang collapsed.

"The first thing that ran through my mind was, `I'm alive,' " Mitchell said. He tried to free himself from dirt piled up to his chest and yelled for help.

The first person to show up was the girls' father, who started digging with his hands to free Mitchell.

"I said, `No, you see me. I'm alive. Get the girls. They might be dead,' " Mitchell remembered saying.

Bush said that when he got his daughters' heads out of the clay, their faces were blue. Only one was breathing when rescue workers freed them all, and all three were pronounced dead at Santa Rosa Medical Center in nearby Milton.

Residents said the clay pit is not fenced. Such pits, left behind when clay is dug out for landfill or cat litter, are common in the area, and fences are not required on older ones.