“The barriers in the past were that [DNA analysis] was slow and expensive. Now it’s cheap and fast,” said Jason Byrd, a professor at the University of Florida College of Medicine who directs Florida’s Emergency Mortuary Operations Response System, the state agency tasked with responding to mass casualty events.

The catch is that in most cases, DNA will only result in identification if one or more family members of a victim have submitted their own DNA through a cheek swab. So far, Maui authorities say they have received relatively few DNA submissions from family members ― just 104 as of Tuesday night.

That number “is far from adequate,” said Richard Selden, founder and chief scientific officer of ANDE, a company with offices in Colorado and Massachusetts that sent two of its rapid DNA-reading instruments and three employees to Maui to help the victim-identification effort.

DNA from a single biological parent or child may be enough to identify a victim, Selden said. But if there are no such samples available, authorities need DNA from one to three other types of relatives.

In the hierarchy of DNA matching, siblings are at the level after parents and children, followed by uncles, aunts, grandparents, half-brothers and half-sisters. When there are no parents, children or siblings of a victim, it may take DNA samples from three or more relatives to establish identity. In the cases of people who don’t have known relatives, their DNA can be compared with samples taken from their toothbrushes, combs or unwashed laundry.

“Based on this, I would expect that at least 300 [DNA samples] will be required, and the number may go even higher,” Selden said.

Emergency personnel have long used more conventional methods to identify disaster victims, from personal effects to fingerprints to medical and dental records.

Mass casualty incidents in which authorities have a list of likely victims ― plane crashes, for example ― are far easier than wildfires, where “you don’t know who’s traveling in an area,” said Kim Gin, the former Sacramento County Coroner who led the effort to identify victims from the 2018 Camp Fire in Northern California.

“One of the big problems in an open incident is that everybody is displaced. They’re all over, and some of them are not coming back into the area,” Gin said, referring to survivors whose DNA might be used to help identify the dead.

Moreover, wildfires can exceed 2,000 degrees, roughly the temperature of lava. That’s hot enough to destroy even tooth enamel, the hardest substance in the human body. Surgical implants, such as pacemakers, are imprinted with unique serial numbers but are sometimes too damaged to be used for identification.

Although temperatures higher than 1,850 degrees have long been thought to destroy DNA, one recent study found a majority of samples were able to survive such heat. In many cases, too, bone helps preserve genetic material.

After the Camp Fire, which forensic anthropologists and other experts have described as analogous to the devastation on Maui, only 22 of the 85 victims were identified using conventional methods such as fingerprints, dental records and surgical implants.

“DNA analysis represented the last opportunity to identify the remaining victims,” according to a paper published in the Journal of Forensic Sciences. Genetic analysis enabled authorities to identify 62 of the remaining 63 victims of the Camp Fire.

The grim search for victims’ DNA

Before DNA technology comes into play, however, the effort to identify fire victims often begins with search teams.

Forensic anthropologists follow up on leads from cadaver-sniffing dogs, firefighters and urban search and rescue workers, said Ashley Kendell, an associate professor and co-director of the Human Identification Lab at Chico State. Kendell spent several days last week assisting the effort to find human remains on Maui.

Wearing P100 respirators to filter the noxious air and hot Tyvek suits to protect their skin from chemicals, forensic anthropologists use trowels, brushes, dustpans and sieves to search for tissue, bone, teeth and other remains.

To the naked eye, burned bone resembles drywall and other building debris. Forensic anthropologists know to look for either dense concentrations of bone, or its honeycomb interior. In places where several people died huddled together, forensic anthropologists try to separate the remains. If they find two left femurs, they know the bones must have come from different victims.

Though difficult to find, teeth can be screened out in a sieve, which has holes that are one-eighth of an inch wide. As they work, the forensic anthropologists keep an inventory of what is recovered, and what is still missing. Kendell said that even when tooth enamel has shattered in the heat, the roots of teeth sometimes survive and can provide DNA.

Those involved in the work describe it as a physically and emotionally draining process.

“When you are in the field, you’re so absorbed in the work that you kind of filter everything out,” said Kendell. “You have to be very scientific about the process.” At the same time, she said, it is mentally exhausting to look up and realize “a whole town is gone.”

Ariel Gruenthal-Rankin, an assistant professor of anthropology at University of Hawaii — West Oahu, also has been helping to recover remains on Maui. “The thing that is at the forefront of my mind is that this is a person who had a whole life with family or friends who are probably missing them deeply,” she wrote in an email. “It is important to me ethically that the person I am examining remains a person to me.”

After collection, remains are prepared for DNA analysis following a range of protocols that have been designed for samples in varying conditions, from minimal to severe damage. Most are collected by swabbing, but bone fragments require more extensive work. Small amounts of a sample are placed on swabs, which go inside the ANDE devices.

The instruments, each the size of a large microwave oven, don’t read all 3 billion base pairs in the human genome, a process that still takes a few days or even weeks. Instead, they examine 27 regions of the genome that have certain repeating sequences. Some people might have five repeats of a specific sequence, for example, while others have six, seven or more.

Taken together, the number of repeats from these 27 regions form a kind of DNA fingerprint. The odds of two people who are not related having the same number of repeats are between 1 in a trillion (a number containing nine zeros) and 1 in a quintillion (a number containing 18 zeros).

A parent and child, however, have the exact same number of repeats in each of the 27 regions of the genome.

But DNA analysis requires comparing at least two samples ― one from victim remains, the other from a relative or from the victim’s toothbrush or clothing. That has been a challenge on Maui, as it has been in other disasters.

“We’re hearing all types of rumors as to why people aren’t coming in,” said Gin, the former Sacramento County Coroner. “It could just be that they’ve been displaced [by the fire] and don’t know where to go.”

County of Maui officials have asked people seeking loved ones to go to the Family Assistance Center in the Monarchy Ballroom at the Hyatt Regency in Kaanapali to provide a DNA sample. Family members who live on a neighboring island or on the continental United States can receive guidance on submitting DNA by calling the FBI Honolulu Division at 808-566-4300 or emailing HN-COMMAND-POST@ic.fbi.gov.

Byrd, the director of Florida’s Emergency Mortuary Operations Response System, added that previously people had many questions about how their genetic material would be used, including, “Am I going to be in a law enforcement database and tracked forever?” In recent years, he said, crime shows on television and ancestry websites have made the public more comfortable with the technology. Maui officials have stressed repeatedly that DNA samples will be used only to identify the wildfire victims.

Gin said that the people who work to identify remains after a disaster get caught up in the task, working for long stretches and forgetting to eat. They know what answers mean to the families of the missing.

“It helps them move on with their lives,” she said.