Expect to hear Indian Point sirens later this evening.

The nuclear plant is testing all of its 172 sirens in Westchester, Rockland, Putnam and Orange counties. They'll sound at full volume for about 4 minutes between 6 and 6:30 p.m.

Federal regulations require regular testing of the sirens in the 10-mile Emergency Planning Zone around the plants. The sirens tell residents in the area that they need to monitor radio and television for information about what is happening at Indian Point.

Plant officials stress that the sirens are not a signal to evacuate. In an actual emergency, the sirens would sound to alert the public to tune in to a local EAS radio or television station for important information and direction.

The plant generates as much as 30 percent of the electricity used in New York City and Westchester County.