BUCHANAN, N.Y. — This is only a test.

The 172 sirens that dot four counties around the Indian Point nuclear power plants will be wailing away Wednesday morning.

The sirens are designed to alert everyone within 10 miles when there’s a serious problem at the plant. But they have to be tested to make sure they will work when needed, and that’s what’s happening at about 10:30 a.m.

The sirens are to sound for about four minutes at full volume. No public response is necessary.