Maui County Emergency Management administrator Herman Andaya, who was criticised by local residents and media over the island's response to the deadly wildfires that killed at least 111 people, has resigned, officials said.
A statement from Maui County Mayor Richard Bissen cited health reasons.
"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," Mr Bissen said.
The resignation takes place a day after Mr Andaya made his first appearance in a press conference, which came more than a week after the catastrophe destroyed or damaged 2,200 buildings and caused some $5.5 billion in damage. Hundreds of people remain unaccounted for.
Some Maui residents said lives could have been saved had emergency sirens sounded, but Mr Andaya's agency opted against using them, saying they would have been ineffective and confusing.
"The public is trained to seek higher ground in the event that the siren is sounded," Mr Andaya said during Wednesday's press conference, which grew tense at times as reporters questioned the government response during the fire.
"Had we sounded the siren that night, we're afraid that people would have gone mauka (to the mountainside) and if that was the case then they would have gone into the fire," Mr Andaya said.
President Joe Biden has vowed that the US government would remain steadfast in its commitment to help the people of Maui recover, rebuild and grieve after last week's deadly wildfires that incinerated the historic resort town of Lahaina.
In a brief video aired on ABC's "Good Morning America," Mr Biden said the federal government had already sent hundreds of emergency personnel, thousands of meals, and essential supplies such as cots and blankets to the devastated town.
"We will be with you for as long as it takes, I promise you," said Mr Biden, who will travel to Hawaii on Monday to survey the devastation and meet with first responders and survivors.
Hawaii Attorney General Anne Lopez has said she will appoint a private, third-party agency to investigate and review how state and county officials responded to the deadly wildfire.
State Governor Josh Green has tasked Ms Lopez with carrying out a comprehensive review of actions taken before, during and after the fire, and the third-party investigation will be a part of that effort.
The review will likely take months, Ms Lopez wrote.
Hundreds of volunteers have come to the aid of displaced Lahaina residents, many of whom are now sleeping in Maui County-run shelters, at the homes of friends and relatives and in donated hotel rooms and vacation rentals.
Volunteers are donating supplies, helping distribute food and water and providing emotional support to many of their fellow Maui residents.
"We're all one big family in Maui, we call it 'ohana,'" said Louis Romero, a 55-year-old retired battalion chief for the island's fire department, who is helping run a crisis-relief hub. "You don't have to be blood relatives to consider you family. That's the Hawaiian way. We help each other."
