LEONARDTOWN, MD – St. Mary’s County Government’s Department of Emergency Services (DES) is advising residents that additional testing of the Calvert Cliffs Nuclear Power Plant emergency warning sirens is scheduled to take place Wednesday, June 3 through Friday, June 5, 2026, at various intervals throughout the day.

The additional testing follows the previously announced semi-annual full-volume siren test scheduled for Monday, June 1, 2026, at noon. The extended testing is being conducted to ensure the intended sound output of individual sirens throughout the warning system.

Residents throughout St. Mary’s, Calvert, and Dorchester counties may hear the sirens during the testing periods and are encouraged to share this information with family, friends, and neighbors to help increase public awareness of the testing schedule. In St. Mary’s County, the additional testing will involve two sirens located near the MD 235/MD 245 intersection and near Shady Mile Drive, in California, Maryland.

The testing is conducted to check siren operation and increase public awareness of the alert and notification siren system. The warning system consists of sirens located within the 10-mile radius surrounding Calvert Cliffs Nuclear Power Plant. The sirens are not a signal to evacuate, but rather a warning to tune to a local television or radio station for information and instructions from emergency management officials.

Knowing what to do before, during, and after an emergency is a critical part of being prepared and may make all the difference when seconds count.

Learn more about and prepare for potential emergencies at: www.stmaryscountymd.gov/em.