Twenty-eight of the state’s 386 sirens that are intended to warn residents and visitors of an impending emergency — and a second alert to warn of an attack such as a North Korean nuclear missile strike — malfunctioned across the islands during this month’s regular test.

The next test is scheduled for Tuesday at 11:45 a.m.

Most of the malfunctioning sirens — 13 — were on Oahu, which has the most sirens of any island — 171, according to the Hawaii Emergency Management Agency.

Seven of Hawaii island’s 83 sirens also had no sound or were out of service; Five of Maui’s 78 sirens malfunctioned, in addition to three of Kaui’s 54 sirens, according to the Hawaii Emergency Management Agency.

Even with 28 sirens out of service, 92.75 percent of the sirens worked as intended.

The sirens that failed are on a list to be “retrofitted, repaired or replaced” within 12 months, said Richard Rapoza, spokesman for the Hawaii Emergency Management Agency.

The sirens are designed to emit a one-minute, “attention alert” steady tone, followed by a one-minute “attack warning signal” wailing tone.

“The Attention Alert Signal informs residents to turn on a radio or television for information and instruction for an impending emergency, or if in a coastal inundation area, evacuate to higher ground,” according to the Hawaii Emergency Management Agency. “The Attack Warning Signal directs residents to seek immediate shelter and remain sheltered in place until an all-clear message is broadcast over radio or television.”

People around Oahu’s Campbell Industrial Park may also hear a “European ambulance sound” that’s meant to warn of a hazardous materials incident.