Dozens of people were injured early Sunday morning at a nightclub in Rochelle Park, New Jersey when a temporary dance floor constructed over an indoor pool collapsed, sending over 50 partygoers into the water. Thirty-five people were taken to the hospital and dozens more were treated for minor injuries when the floor made of plywood and plexiglass gave way.

Witnesses said a large number of people began dancing at once when the disc jockey played a popular song. The floor failed shortly thereafter. Several people sustained head and neck injuries while others were knocked unconscious during the fall. A number of people suffered cuts, sprains and broken bones.

Authorities are investigating whether the nightclub, Metro Lounge, violated building codes.