42-year-old Sean Benschop appeared in court Tuesday. Prosecutors have added a third degree murder charge to the six counts of involuntary manslaughter he already faced.
Benschop, a heavy equipment operator, is accused of being high on marijuana and painkillers while on the demolition job at 22nd and Market streets last June.
The judge also upheld the same six murder charges previously lodged against demolition contractor Griffin Campbell.
Benschop and Campbell are the two charged so far in the horrific building collapse that left six people dead and 13 more injured when an unsupported back wall being torn down fell into the adjacent Salvation Army store.
Prosecutors say the collapse was the result of Benschop and Campbell ignoring standard safety procedures despite warnings that the excavator could bring debris crashing on the store that was full of employees and customers.
Benschop and Campbell were both held over for trial.
Both men are also charged with six counts of involuntary manslaughter.
Information from The Associated Press was used in this article.