The men were working on flashing on a building on the 3400 block of Walnut Street when, shortly before 1 p.m., the scaffolding collapsed.
It's estimated they were 40 to 50 feet above street level. The pair part of a larger work crew that was doing restoration work on the east wall of the University of Pennsylvania's Van Pelt Library.
Philadelphia Firefighters using Ladder 9 rescued the pair. The two made it to the bottom. They declined a trip to be checked out at a hospital.
Inspectors say the workers' safety harnesses safely held them in place so they did not fall to the ground at the time of the mishap.
The thinking by investigators, an unexpectedly large number of bricks fell onto the scaffold overloading it causing the structures to collapse.
Federal OSHA inspectors are said to be leading the investigation into the workplace accident.
To Whom it May Concern:
Allan Johnson of West Philadelphia was walking along the 3400 block of Walnut when he heard the bricks falling. He looked up and saw one of the workers on the broken scaffold. He said the man was held up by a safety cord. Without the safety harness, he said the situation would have been " much much worse."
As of late Monday afternoon, the restoration crew was placing lumber to areas where bricks are missing to prevent any further problems with the library's walls.