There was no immediate word on the condition of the second worker as rescuers remain on the scene.
The accident happened around 11:20 a.m.at 40 Featherbed Lane in Lower Providence Township.
The view from Chopper 6 showed a number of firefighters and medics on the scene.
One firefighter was in a ladder, being lifted to the top of the tall, blue water tank.
There was no immediate word on if there was any water inside.
There was also no word on how this accident happened.