Miami-Dade police said at least two men were shocked by a live power line while lifting tiles onto a residential rooftop in Kendall.
Police said they feared the worst after transporting one of the workers who was found unresponsive and turning blue on the ground off Southwest 112th Street and 145th Avenue.
Investigators told Local10 News the men were using an extended conveyer belt attached to their truck when it possibly got too close to the wires.
At least one operator on the ground and one on the roof were shocked and thrown back, according to witnesses, who said they heard a loud pop.
Elizabeth Salom, who lives across the street, said she heard the noise and ran out to find one worker screaming for help and a second nearby unresponsive.
Police said the men were taken to Kendall Regional Medical Center, where they are now listed in stable condition.
The truck the men were using had a Miami Tiles Deliveries Corp. banner on the side of it.
Florida Power & Light arrived at the scene to secure the power lines and return power to area houses as the investigation continues.