A heavy equipment operator charged in a Philadelphia building collapse that killed six people and injured 12 has pleaded guilty to involuntary manslaughter and other charges.

Authorities have said 44-year-old Sean Benschop (BEN'-skop) was impaired by painkillers and marijuana when the wall collapse buried victims inside an adjacent Salvation Army store.

Prosecutors have agreed to recommend a sentence of not more than 10 to 20 years.

The plea Tuesday resolves charges that included third-degree murder.

Fifty-year-old demolition contractor Griffin Campbell also faces murder charges in the June 2013 collapse.

Defense lawyers have previously called them scapegoats.

Authorities have not charged building owner Richard Basciano, who hired Campbell's cut-rate bid for the work.