CONCORD, N.H. (AP) – The demolition of three smokestacks at Berlin’s former pulp mill was meant to be a spectacle, but the big event went awry when flying debris injured seven people, none seriously.

The demolition Saturday drew thousands of spectators to witness the end of the era when pulp mill smokestacks ruled Berlin’s skyline.

The first two smokestacks came down without a hitch. The injuries occurred after explosives failed to topple the last of the three stacks and workers used to a cutting torch to loosen its foundation before it finally came down.

Seven people were treated at a hospital for cuts and bruises; one of them, 52-year-old Sherry Fontaine, suffered a broken rib.

She said she was part of a crowd behind a barrier on a street next to a mill parking lot when the stack fell hundreds of feet away.

“All of a sudden it was almost like a swarm of black bugs or something coming toward us,” Fontaine said in a telephone interview. Sunday. She said she and her husband were running for cover when she felt rocks pummel her body, adding, “The pain was excruciating.”

The pulp mill in the northern New Hampshire city closed in May 2006; a plant to convert biomass into energy is planned for the site.

Jim Redyke, president of Tulsa, Okla.-based Dykon Explosive Demolition, said barriers were put up to keep spectators several hundred feet away, and he was skeptical that large chunks of debris could have fallen far from the stack.

“Perhaps they moved up closer than they were supposed to have been,” he said.

Except for the delay, the demolition went as it was planned, he said.

“It went and fell exactly where it was supposed to,” he said.

But Redyke also said the debris shower was unexpected.

“That was one of those things. Sometimes they’re very contained, sometimes they scatter, that’s why they had a zone. That’s why we put some protection up there. It went farther any anybody expected,” he said.

Police Sgt. Don Gendron said Sunday that officers were on patrol during the demolition, but he did not know any details. He said he did not expect there would be any criminal charges.

“I would think there would be some civil issues, but that’s up to the lawyers,” said Gendron.

Coos County Family Health Services sold tickets at $5 apiece for the chance to push two of the detonation buttons. The raffle raised more than $2,300 for dental care for local children.

Home video broadcast on WMUR-TV shows two figures at the base of the smokestack running away as the concrete tower begins to tilt.