Blood tests show the heavy machinery operator involved in Wednesday's deadly building collapse at 22nd and Market streets detected marijuana and prescription pain killers, according to a news report.
CBS Philadelphia reports that 42-year-old Sean Benschop had the drugs in his system when the samples were taken about two hours after the collapse.
Benschop, who was treated for minor injuries, has a history of arrests on charges that include drugs, theft, assault and traffic violations.
Investigators also noted that he was speaking unusually slowly and quietly after the incident, sources told CBS. The television station also reported that Benschop told authorities he was taking pain medication after a recent cut to his finger.
The collapse left six people dead and 13 injured.
Philadelphia police directed questions about Benschop's drug-test results to the District Attorney's Office. A spokeswoman there could not immediately be reached.