The monthly test of the city’s emergency outdoor siren warning system and live audio broadcast is scheduled for 11:45 a.m. today.

The city Department of Emergency Management and Hawaii State Civil Defense said residents should hear a 45-second steady tone on all sirens.

Also, residents near Campbell Industrial Park, Honokai Hale, Makakilo, Kapolei Regional Park, Kapolei Golf Course, and the Coast Guard Station at Kalaeloa may also hear a “whooping” tone following the siren test, official said. This tone is a test of the hazardous materials incident warning system.

If the sirens are activated in a real emergency, residents should turn to any radio or TV station for essential information and instructions.