Officials say there is no cause for alarm at the Peach Bottom Atomic Power Station.
York County Office of Emergency Management spokesman Carl Lindquist said the office and the county's 911 center received numerous telephone calls from people reporting that the sirens around the plant were activated late Tuesday morning.
Lindquist said it's unclear why the sirens sounded.
If there had been an emergency at the plant, he said the sirens would have sounded for three minutes.
The sirens are used to notify residents of an emergency. They are not a signal to evacuate, but to tune to the local Emergency Alert Broadcast Station.