The accident happened at around 1 p.m.
Herndon Police as well as Fairfax County Fire and Rescue crews responded to the scene after receiving the call at 1:10 p.m. According to an emergency alert, they performed CPR on the man and transported him to a nearby hospital.
Herndon Police said OSHA is conducting an investigation but that preliminary findings indicate the man lost his footing, causing him to fall from the roof.
The man's identity has not been released pending notification of family.
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