Three Mile Island Generating Station

Emergency Siren Test

An Emergency Siren Test is scheduled for December 3, 2020

Sirens will sound for three minutes at 12:15 p.m.

Exelon Generation will conduct its semi-annual, full volume test of the emergency warning sirens surrounding Three Mile Island (TMI) Generating Station on December 3, 2020 at approximately 12:15 p.m. 

This will be the final siren test for TMI Unit 1. Although TMI Unit 1 permanently shut down on September 20, 2019, the siren system remains in operation in accordance with local, state and federal emergency planning requirements. In January 2021,  those emergency procedures and processes will be discontinued as part of the decommissioning process. 

The emergency warning siren system consists of 96 sirens located in parts of Cumberland, Dauphin, Lancaster, Lebanon and York counties within a 10-mile radius of TMI. The sirens are not a signal to evacuate, but a warning to tune to a local emergency alert broadcast television or radio station. County emergency management authorities activate the sirens, which can be used in the event of any emergency, including severe weather.