In this image taken from video, Maui Emergency Management Agency Administrator Herman Andaya speaks during a news conference in Wailuku, Hawaii, Wednesday, Aug. 16, 2023.

The head of Maui County's emergency management agency resigned on Thursday, a day after he defended his decision to not activate sirens during catastrophic wildfires that have taken more than 100 lives.

Maui Emergency Management Agency administrator Herman Andaya cited health reasons for his resignation, which took immediate effect.

Andaya was asked Wednesday whether he regretted not activating emergency sirens as wildfires spread across West Maui: "I do not," he said at a press conference

Andaya said the sirens are mainly used for tsunamis and the public is trained to seek higher ground. Escaping to higher ground would have been dangerous during the wildfires, he said.

"We were afraid people would have gone 'mauka,'" Andaya said, using a Hawaiian word for mountainside. "And if that was the case they would have gone into the fire."

Maui County Mayor Richard Bissen said he would announce a replacement for Andaya soon: "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," Bissen said in a statement Thursday.

At least 111 people have perished in the blaze as of Wednesday, with the death toll expected to rise as search dogs continue to comb the wreckage of the devastated historic town of Lahaina. The inferno is the deadliest wildfire in the U.S. in more than a century and the worst disaster in Hawaii state history.

State and local emergency management officials face growing scrutiny over whether they did enough to alert the public as the wildfires spread.

Hawaii Attorney General Anne Lopez announced on Thursday that she will tap an independent investigator to review the state and local response to the wildfires.

"This will be an impartial, independent review," Lopez said in a statement.

Hawaii Gov. Josh Green said Wednesday the review is not a criminal investigation.

"It's not a criminal investigation in any way," Green said. "Right now we are working to find out how we can make sure it's safe as we go through hurricane season, as we deal with the reality that there will be fires month in and month out for the decades to come."