This is an edit of my first post. Previously listed information was incorrect
Recently I have been researching the Emergency Planning documents that were of the former Maine Yankee Nuclear Power Plant, and I have learned a lot about the siren system that was in place when the plant was operational.
In July 1981, the Maine Yankee had installed a Emergency Warning Siren System composed of 6 ACA Cyclones, 1 Allertor & 1 EOWS 1212 within a radius of 5 miles from the plant.
For the remaining 5 miles within the 10 mile Emergency Planning Zone, or in the event of siren failure, a Mobile Alerting System was used. Emergency vehicles would use their sirens to sound a steady alert tone followed by voice announcements to get the attention of the public.
In 1989, the system was upgraded with the addition of 29 Whelen 3016 units. The installation of the new sirens had provided full coverage for the Emergency Planning Zone, eliminating the Mobile Alerting System as a primary means of notification
The system was silent tested monthly. Full scale audible tests would take place in October.
Due to growing safety concerns, the plant was closed prematurely in 1997. During plant decommissioning in 1999, 24 of the 37 siren units were removed. The remaining 12 were left behind for municipal use.
Some of the locations where units are still standing would be the Boothbay Harbor Fire Department, Bath City Hall, Five Islands Fire Department, and the Town of Phippsburg.
I have maps available of the siren locations, just let me know!