Two employees at an Edmonton lumberyard were briefly buried under slabs of plywood Saturday morning when several warehouse stacks toppled onto them.

“I just started hearing shelves crashing over and a shelf fell on me but I was able to kind of push it off and crawl out,” lumberyard employee Aric Kuecy told CTV Edmonton. “It was just a domino -- one, two, three, four.”

Two employees were trapped in the incident, Kuecy added.

“Just yelling, ‘Help! Help! We’re over here,’” he said. “I saw the one woman, she stuck her hand out. She was buried in-between two shelves and a bunch of railings.”

Police and fire crews quickly responded.

“[Police] ran in there shoulder-to-shoulder with the Edmonton fire department and just started throwing lumber around for what was about half an hour to get to the bottom,” Edmonton police Staff Sgt. Randy Wickins said from the scene.

The two employees were taken to hospital and treated for non-life threatening injuries.

“Seeing the volume of lumber that fell over, it’s amazing that nobody else was injured,” District Fire Chief Brian Lees said. “They’re lucky to get away with just the injuries they did have.”

Lees likened the accident to a “domino effect.”

“All the product that fell off the one fell onto the floor,” he said. “Then the next one fell, and more and more… The pile is about 30 feet high.”

Police say it’s still too early to determine what caused the accident, but it could have happened because the lumberyard’s shelves may not have been bolted to the floor.

“From what I understand, the shelves were not bolted down, so there’s a lot of weight up in the air -- 14 feet up,” Wickins explained. “And then someone was up on a ladder, up at the very top, and they tipped the first shelf over and then shelf after shelf after that came crashing down.”

Occupational Health and Safety officers arrived on scene after the rescues were complete to begin their investigation. According to those officers, both employees have been released from hospital.

With files from CTV Edmonton