By Nouran Salahieh, Raja Razek and Holly Yan, CNN

(CNN) — The administrator of Maui’s emergency management agency has resigned, citing health reasons, Maui County said Thursday – an announcement that comes a day after he defended the silence of the island’s siren system last week during the deadliest US wildfire in more than 100 years.

The resignation of Maui Emergency Management Agency Administrator Herman Andaya is effective immediately, the county said.

The wildfires that started August 8 have killed at least 111 people – including children, largely in the area of the town of Lahaina on Maui’s west coast. And most of the burn zone still needs searching, officials have said.

“Given the gravity of the crisis we are facing, my team and I will be placing someone in this key position as quickly as possible, and I look forward to making that announcement soon,” Maui County Mayor Richard Bissen said.

Details about the health reasons that Andaya cited were not immediately available. CNN has sought comment from Hawaii Gov. Josh Green.

A spokesperson for the Hawaii Emergency Management Agency said last week that no one attempted to activate Maui’s 80-alarm all-hazard outdoor siren system – part of a larger statewide network – as the deadly fires spread August 8.

At a Wednesday news conference, Andaya was asked whether he regretted not sounding the alarms. Andaya said, “I do not,” telling reporters he worried that if they had sounded, many residents would’ve gone inland and “would have gone into the fire.”

US Sen. Mazie Hirono of Hawaii criticized that response later that day, calling Andaya’s assessment of the situation and comment about not regretting his decision “premature.”

Before Andaya’s resignation was announced, state Sen. Angus McKelvey, who represents the devastated town of Lahaina and lost his own home in the fires, blasted Andaya’s response as “insulting.”

“I’ve heard the line that ‘people would have panicked and ran up to the mountains because it’s a tsunami siren.’ … It’s insulting to think that people would be that clueless, that they wouldn’t know that sirens blasting was because of the fire,” McKelvey told CNN on Thursday. “These are not tsunami sirens. They’re disaster sirens.”

It remains unclear why exactly the sirens system weren’t used, as narratives about the silence have shifted. In interviews with CNN, Green has said some sirens were broken. The governor has asked the state attorney general to review the fire and officials’ response, including the alarms’ silence.

The number of residents unaccounted for is “probably still over 1,000,” Green told CNN on Wednesday.

Search crews are expected to keep scouring the charred debris of more than 2,000 burnt homes and businesses for days, the police chief said. Some are working despite immense personal grief.

“Realize that the responders that are going out there are recovering their loved ones and members of their families,” he said.

Power company also faces scrutiny

While the cause of the fires hasn’t been determined, Hawaiian Electric – the major power company on Maui – also is facing scrutiny, for not shutting down power lines when high winds created dangerous fire conditions. A company that runs a sensor network on Maui says it detected major utility grid faults hours before fires started.

Hawaiian Electric said publicly in 2019 it would conduct drone surveys to identify areas vulnerable to wildfires and determine how to help keep residents and infrastructure safe.

But between 2019 and 2022, Hawaiian Electric invested less than $245,000 on wildfire-specific projects, according to The Wall Street Journal, citing regulatory filings.

Hawaiian Electric also didn’t seek state approval to raise rates to pay for safety improvements until 2022, and the rate hike has yet to be approved, the Journal reported.

In a statement to CNN, the company said it has spent roughly $84 million since 2018 on maintenance and vegetation management in Maui County, including trimming and cutting down trees and upgrading equipment.

“There are many elements of wildfire mitigation that don’t get counted specifically as mitigation activities, including vegetation management, grid hardening and pole replacement and routine line and equipment inspections,” the company said.

What we know so far

While many questions remain, here’s the latest on what we know about the historic fires:

• Fires are still raging: The most destructive blaze, the 2,170-acre Lahaina fire, was 89% contained as of Wednesday night, Maui County posted on Facebook.

Several other wildfires are still burning in Maui, including the 1,081-acre Olinda fire, which was 85% contained as of Wednesday, and the 202-acre Kula fire, which was 80% contained, according to Maui County.

“We are spread thin, and we are at multiple locations throughout the island,” Maui County Fire Chief Brad Ventura said. Still, “If something should come, we’re ready for it.”

• Authorities identify more victims: Melva Benjamin, 71, Virginia Dofa, 90, Alfredo Galinato, 79, Robert Dyckman, 74, and Buddy Jantoc, 79, all of Lahaina, perished in the blazes, Maui County officials said Wednesday. Other victims have been identified by their families.

• Biden set to visit: The White House said the president and first lady will visit Maui on Monday.

Authorities ask for DNA samples to identify victims

Crews have searched roughly 45% “of the affected, impacted area, which is about a 5 square-mile area,” Bissen, the mayor, told CNN’s Erin Burnett on Thursday.

Combing the ashes of what used to be homes, businesses and historic landmarks has been arduous. And identifying those killed won’t be easy, as remains are largely unrecognizable and fingerprints rarely found, the governor said.

A genetics team will help identify remains “so that we can make sure that we’re finding who our loved ones are, and that we make the notifications with dignity and honor,” Pelletier said.

Authorities have asked relatives of the missing to provide DNA samples.

Brenda Keau’s husband gave a DNA sample to help find his 83-year-old mother, Keau told CNN. The couple found her home in hard-hit Lahaina burned to the ground.

“We accepted it on the day that we saw that there was no house,” Keau said. “But you never give up hope.”

At least 40 canines from 15 states have joined in the search, said Jeff Hickman of the Hawaii Department of Defense.

“We’ll start to bring closure to those who need it and identify those missing,” he said.

Firefighters battled blazes as their own homes burned

When ferocious winds hurled flames across and quickly overwhelmed crews on August 8, some firefighters knew their own homes could burn.

“The people that were trying to put out these fires lived in those homes – 25 of our firefighters lost their homes,” Bissen said Wednesday.

Maui firefighter Aina Kohler was on the front lines that day and stuck to her mission to save lives – even as her house burned to the ground, she told CNN affiliate KITV. By the time flames reached her home, she said, firefighters had run out of water.

“That was honestly the most disheartening thing of my life. I felt the supply, and I’m like: It’s limp. Just leaving a house to burn because we don’t have enough water is like something I’ve never experienced before,” she said.

Two of Kohler’s fellow firefighters also lost their homes while battling the fires, she said.

“They watched their homes burn as they fought the fire for other homes in their neighborhood,” Kohler said. “That hit really hard.”

Role of power lines scrutinized

A sensor network run by Whisker Labs detected an “increasingly stressed utility grid” on Maui, beginning late August 7 and into the next morning, the company’s CEO Bob Marshall told CNN on Wednesday.

“Through the overnight hours, when all the fires ignited, we measured 122 individual faults on the utility grid,” Marshall said.A fault – a short circuit or partial short circuit – could cause electric current to leave its intended path, which could lead to a fire, Marshall said.

Video taken at the Maui Bird Conservation Center in Makawao appears to show a power pole faulting just before 11 p.m. on August 7. Soon after, what appears to be flames are seen in the video, first reported by The Washington Post.

The sensor system provided “verification that, indeed, this was very likely caused by a fault on the utility grid,” Marshall said.

The Makawao fire was hours before and miles away from the fire that decimated the historic portions of Lahaina in Western Maui. But sensors detected faults on the grid before that fire, too, Marshall said.

A class-action lawsuit filed over the weekend alleges the wildfires were caused by Hawaiian Electric’s energized power lines that were knocked down by strong winds.

The company and its subsidiaries “chose not to deenergize their power lines after they knew some poles and lines had fallen and were in contact with the vegetation or the ground,” the suit alleges.

Precautionary shutoffs have to be arranged with first responders, Hawaiian Electric Vice President Jim Kelly told CNN on Sunday in an email, adding the company doesn’t comment on pending litigation.

“Electricity powers the pumps that provide the water needed for firefighting,” Kelly said.

Hawaiian Electric is also eager to find answers, a company spokesperson said.

“We know there is speculation about what started the fires,” spokesperson Darren Pai told The Washington Post. “And we, along with others, are working hard to figure out what happened.”