"Unknown and unexploded" dynamite on Commercial Street Bridge detonates day after implosion, PennDOT says

About 24 hours after the Commercial Street Bridge was imploded, crews hit dynamite that had unknowingly failed to detonate, causing another explosion that sent workers running.

Around 7:40 a.m. on July 17, PennDOT cameras captured the moment at the Parkway East construction site. It showed a blast followed by a plume of dust filling the air, almost exactly 24 hours after contractors blasted the old Commercial Street Bridge. In the video, you can see what appears to be workers running away, as others turn to look, trying to figure out what happened.

District 11 Senior Assistant Construction Manager John Myler confirmed to KDKA that as crews were cleaning up debris from the demolition of the bridge, a piece of equipment hit an explosive that hadn't gone off in the initial blast.

"Everybody was caught off guard by it for sure," Myler said. "One of the operators struck a piece, doing demolition of the bridge, struck a piece of unknown and unexploded dynamite, and that set it off." 

The demolition contractors initially combed the area after the implosion on Thursday and gave the all-clear, but following this incident on July 17, they were called back to the site to make sure there was no other unexploded dynamite remaining.

"For some reason, this one stick apparently was not detonated," Myler said. "Certainly unsettling to come across something like that."

About 12 hours later, workers got another all-clear and crews were allowed to return to work.

Myler said no one was hurt and no equipment was damaged, and he said PennDOT doesn't plan to pursue any further investigations with the contractor.

"This was just an errant mistake in that process," Myler said.