“You should stay inside and stay tuned,” advised Lt. Col. Charles Anthony, state of Hawaii Department of Defense director of public affairs.

If a nuclear missile detonated in Hawaii, “you might have 10 percent of the population either instantly killed or killed shortly thereafter” because they would be at ground zero, Anthony said.

“But 90 percent of the population will survive as long as they shelter in place and not (be) exposed to radiation fallout,” he said.

And, if people are in a house or building, they should shut the windows and the shades to prevent debris from coming inside.

The Hawaii Emergency Management Agency says that, once a real alert is given, residents and visitors would have less than 12 to 15 minutes before missile impact. So, people “must immediately” seek shelter in a building or other substantial structure.

Anthony’s comments and information from the agency come after questions from the public following the Jan. 13 false alarm of an incoming ballistic missile. A cellphone alert told people a missile attack was inbound to Hawaii. “SEEK IMMEDIATE SHELTER. THIS IS NOT A DRILL,” the warning said.

It took 38 minutes before the Hawaii Emergency Management Agency on Oahu issued an all-clear message to cellphones, acknowledging that there had been a false alarm.

People panicked, sought shelter, packed up their vehicles and even tried driving to Haleakala, while others hid in closets and said their last goodbyes.

The erroneous warning was sent at 8:07 a.m. during a shift change at the EMA agency when an employee, during a routine test, hit the live alert button at the agency’s Diamond Head headquarters. The employee has been reassigned to another job without access to the warning system amid an internal investigation.

Gov. David Ige has apologized publicly repeatedly. He has pledged there would be no repeat of such a false alarm, and he has said procedures have been implemented to upgrade the emergency warning system.

The incident opened the public and government’s eyes to how ill-prepared the state and its people have been for a possible missile strike.

“We got to educate the people of Maui County so they know what they need to do. Some people did not,” said Maui County Communications Director Rod Antone. “The side benefit of this unfortunate incident is that people are finally paying attention.”

While the false alarm came on the weekend and when people may still have been sleeping in at home, others were already out, driving to soccer games and beginning to run errands.

If there was a real attack, motorists and their passengers should quickly find a building or any type of shelter, Anthony and Antone said.

If there’s no structure nearby, people could get into a ditch and “cover your head,” Antone said.

Anthony warned that people’s cars may not operate because the electromagnetic pulse triggered by the nuclear blast can disrupt or destroy electronics.

In another scenario, someone in an old plantation house or structure made out of wood and glass should seek more substantial shelter in just a few minutes, Antone said.

But he doesn’t advise driving long distances because there would be no time with a missile strike happening in less than 15 minutes. He pointed out that he heard of people that day driving up to Haleakala.

Unlike the false alarm when the alert went out to cellphones only, sirens would sound during a real emergency, and there would be news scrolls on television, Antone said.

Hawaii emergency officials have said the outdoor sirens did not go off during the false alarm because they are on a separate system that was not engaged during the mistake.

Some people on Oahu military bases may have heard sirens, but those were manually activated by base personnel, state officials said.

Missile impacts

Government officials estimate that North Korea could produce a nuclear device as large as 150 kilotons, Anthony said. A kiloton is a unit of explosive power equal to 1,000 tons of TNT.

The estimate is based on the country’s latest nuclear test in September. That showed the rogue nation could produce a nuclear weapon of about 100 kilotons.

By comparison, the bomb dropped on Hiroshima was 15 kilotons.

Working with the worst-case scenario, if a 150-kiloton device were detonated 1,000 feet above the ground, it would create a nuclear blast zone of 6 to 7 miles in diameter, Anthony said.

While it would be fatal to be in the blast zone, Hawaii’s islands are much larger than 6 to 7 miles in diameter, meaning that there would be many survivors after the initial blast, he said.

“That’s the whole reason why you need to have a nuclear plan in place,” he said.

As for radiation drifting on winds from the blast site, Anthony said that would depend on various factors, including surface and atmospheric winds, temperature and other weather conditions.

Radiation could impact a wide area or even just a small area. Maui could be impacted even if ground zero were on Oahu, he said.

Radiation particles cannot be seen. But they would be attached to dirt and ash and debris from buildings and other items that will go into the mushroom cloud.

It would then go into the atmosphere and begin to fall out.

“You should stay inside and stay tuned,” Anthony said.

It is important to have a battery or crank-operated radio on hand, especially since the nuclear electromagnetic pulse triggered by the nuclear blast can disrupt and even destroy electronics. It can disrupt radio signals as well.

But Anthony said that, if the blast were on Oahu, Maui radio stations may still be able to send out signals.

As for after a nuclear missile explodes, “there is a very fast drop-off in the level of radioactivity after 48 hours,” he said.

“That doesn’t mean it is absolutely safe,” Anthony added.

But the radiation “drops off entirely at the 14-day mark.”

Anthony said that if no all-clear were given or heard, because electricity is out or radio signals are down, residents should manually count the days up to two weeks before it’s clearly safe to head outdoors.

As for staying protected after the missile explodes, Anthony said the farther away someone can get from the fallout the better.

For example, for someone living in a 20-story building, the best place would be in the middle on the 10th floor because there would be a lot of concrete separating the person from where fallout could land, which is on top of the building and on the ground.

If someone has a basement that is two stories below ground, that would provide protection because there is dirt and concrete separating the person from the fallout.

If people shelter in these types of areas, Anthony said they should bring food and water.

If people have been exposed outside to radiation or think they have been exposed, Anthony recommended hosing them down before going into the building. They also should remove contaminated clothes and wash their hair.

More information on what do in an event of a nuclear blast, including how to prepare and how cope with radiation exposure, visit www.ready.gov/nuclear-blast.

Thinking the unthinkable

Will a missile attack happen?

“It’s a very low probability,” Anthony said.

The chances are higher that the state would be hit by a Category 4 hurricane than a North Korean ballistic missile, he added.

When conducting a threat analysis, Hawaii has flooding, brush fires, cyberattacks, earthquakes, hurricanes and tsunamis and others to be concerned about, which are higher threats than a missile attack, he said.

But since North Korea has shown the capability having an intercontinental ballistic missile reach Hawaii, “it’s a potential threat,” Anthony said.

He added that the country has not demonstrated the capability of accurately delivering a nuclear payload, and it hasn’t shown that one of its nuclear warheads could survive re-entry into the atmosphere.

In all, Anthony said that an emergency kit for a hurricane is virtually identical to one for people to survive a nuclear blast.

This includes having water, food, medication and even petty cash.

* Melissa Tanji can be reached at mtanji@mauinews.com.