An emergency warning system for Exelon Power's Muddy Run Pumped Storage Facility will be tested this week in parts of York County.

Sirens will be tested at 10 a.m. Thursday in communities near the Lancaster County site, including Drumore Township in Lancaster County, and Lower Chanceford and Peach Bottom townships in York County.

During the two-minute alert, a brief tone will sound, followed by the words, "This is a test, this is a test," according to a company news release.

The system is routinely tested every three months at 10 a.m. on the second Thursday of January, April, July and October.