In this Oct. 9, 2017, file photo, firefighters battle flames along Jamboree Road in Orange, Calif. (Photo: Will Lester/The Orange County Register via AP, File)

Identifying a body when only bones are left behind can be difficult—and even more difficult is identifying skeletal remains that have been damaged and dispersed in the aftermath of a fire. Forensic anthropologists have a variety of tools and techniques for examining the remains of fire victims, using increasingly advanced technology to scan debris and increasingly precise methods to reap clues from the minute details of bones.

Depending on how intact the remains are and how much damage has been done to the body by the heat of the flames, investigators will turn to different methods in order to make the quickest and most reliable identification possible. According to Anthony Falsetti, a board certified forensic anthropologist and professor at Arizona State University’s School of Mathematical and Natural Sciences, investigators will often look to a victim’s dental records first, if possible.

“Most of us have dental records available and we don’t have our DNA records available,” Falsetti explained, in an interview with Forensic Magazine. “So for DNA in this situation, you might not be comparing it to an antemortum sample of an individual—unless they’re a service member—but a family reference sample. It’s just more complicated to do it that way; dental is usually the first thing that you’d want to do.”

DNA comparisons also take more time than dental comparisons, Falsetti said, but can be used if necessary, when dental information is not available. However, remains that are badly burned may not yield a usable DNA sample, due to the effects of extreme heat.

“It all depends on how much—and there’s no delicate way to put it—how much thermal damage there is,” Falsetti said. “Because DNA is a cellular structure, and heat damages that cellular structure to the point where it makes it very difficult to recover.”

Forensic anthropologist and Arizona State University professor Anthony Falsetti. (Credit: Arizona State University)

Even without the availability of soft tissues on the body, forensic anthropologists can still estimate traits such as sex and age from bone structure, which is why “anything that looks like bone” will be diligently collected from a fire scene once an investigation starts, Falsetti said. The anthropologists will then separate bone from non-bone, and human bone from animal bone, before gathering as much information as possible from what is left.

Comparing burned remains to a list of missing people can also be aided by the availability of medical records, showing whether a missing person experienced a bone fracture or other anomaly identical to that found on the bones recovered from a fire. And even just fragments of dental structures and teeth can be reconstructed for comparison to dental records; dental, medical and DNA comparisons may all come together to confirm a final ID of severely damaged remains.

Though forensic anthropology is becoming more advanced, and DNA tests are becoming more sensitive and precise, there are some cases in which burned remains are too damaged to be identified. And a mass fatality event can make the work even more difficult, with the chaos of a fire scene—and even the large amounts of water that come down from the fire suppression systems of buildings—can cause human remains to be dispersed and “comingle,” Falsetti said.  

Reliable and efficient identifications are incredibly important in the wake of mass fire fatalities, such as the 42 deaths as the result of California wildfires this month, and the 60 or more victims of the Grenfell Tower fire in London earlier this year. Fortunately, technological advances in the anthropology field have made some processes more efficient—responders can now use handheld radiography devices to locate remains in the field, and even X-ray dental structures among the debris right at the scene, Falsetti said.

Some advancements have even allowed investigators to identify severely damaged remains several years after they were recovered—in August, the identity of one of the victims of the 9/11 terrorist attacks was finally confirmed, 16 years after the attacks occurred. Investigators working to identify the hundreds who died in the attacks have repeatedly used the newest, most sensitive technologies in their efforts, sometimes pulverizing pieces of bone in order to extract DNA from the fragmented remains.

Falsetti says the recovery effort in California will benefit from the collaboration of forensic professionals.

“In the California case, there’s a whole team of anthropologists that they’ve brought in to help them with this process, so that’s a good thing,” he said. “They’ve got the right people working together on this."