The fire department says eight people were injured, seven seriously, when packed shelving units collapsed at a Bronx dollar store.

The shelves fell at about 3:45 p.m. Monday at the Discount Outlet on Morris Avenue in the Melrose neighborhood.

Fire officials say the collapsing shelves created a cascading effect, burying people under piles of merchandise.

Customer Norma Villafane said she was shopping in a perimeter aisle when she heard "this real thunderous sound."

"When I turned around, all the shelves were tumbling down," she said.

Three to four aisles of shelving tumbled down, hurting eight people and temporarily burying at least two small children, according to fire officials and witnesses.

"You could hear the screaming," said witness Lucy Tirado, who was standing outside the store as her husband went in to buy some air freshener. "I could hear the lady screaming because her kids were under that mess."

Responding firefighters had to remove the goods by hand and cart them onto the sidewalk.

A fire department spokesman says there was no structural damage.

He says none of the injuries, which included broken bones, are life threatening. All were taken to Lincoln Hospital in stable condition.

Tirado's husband was among the injured customers; he had broken bones.

More than 60 firefighters responded to the scene. The fire department says the cause of the shelving collapse is under investigation.

-- Checkey Beckford contributed to this report.