Dive Brief:

• An excavator operator on Tuesday pleaded guilty to involuntary manslaughter in connection with a 2013 demolition accident that killed six people and injured 12 in Philadelphia.

• Sean Benschop, 44, had been charged with manslaughter and accused of operating the heavy equipment after he took the painkiller Percocet and used marijuana on the day of the accident. Benschop, who was working for a demolition contractor that ABC News described as "cut-rate," also had a cast on his arm and had been warned not to use the machinery to demolish an unsupported brick wall.

• As the wall collapsed, it fell onto the building next door — a one-story Salvation Army thrift store — burying its occupants under the rubble. The owner of the contracting company — Griffin Campbell — also was charged with manslaughter, but will fight the charges in court, according to ABC News.

Dive Insight:

At the time of the accident, Philadelphia issued demolition permits without requiring the building owner to file plans or prove that their contractors were qualified, ABC News reported.

Benschop, a native of Guyana and father of six, pleaded guilty to six counts of involuntary manslaughter and 12 counts of reckless endangerment, conspiracy and causing a catastrophe. He faces 10 to 20 years in jail.