Forensic experts in the Office of the New York City Chief Medical Examiner will be using — possibly before the end of the year — state-of-the-art DNA technology to try and identify remains of more than 1,100 victims of the attack on the World Trade Center.
Thousands of pieces of fragmented human remains have yet to be identified because they are too degraded to be analyzed by conventional forensic techniques. They are currently being stored in a special repository at the National September 11 Memorial & Museum complex at the site of the attack.
Earlier this year, the medical examiner's office got approval from state officials to use the new forensic method already used by the U.S. military — known as Next Generation Sequencing, or NGS — to help identify the Twin Towers remains, as well as those of unidentified missing persons generally. The technique, used first in in medical research, has already been adopted by the U.S. Department of Defense to identify World War II, Korean War and Vietnam War dead.
"I think it is a game changer," said Dr. Timothy McMahon, director of the Department of Defense DNA operations for the Armed Forces Medical Examiner System, about the potential progress NGS offers in World Trade Center cases.
Mark Desire, chief of the Office of the Chief Medical Examiner’s missing persons and body identification unit for the city's medical examiner, said his office is receiving training and expects to by the end of the year.
"I am very confident that we will be able to use the most advanced technology that we haven’t been able to do," Desire said during a recent interview at the labs where the testing will happen.
Victims' families welcome new tool
Rosemary Cain of Massapequa, whose 35-year-old firefighter son, George, died in the Twin Towers, was guardedly optimistic that the sequencing method could help. "Whatever they can use would be wonderful."
But she said some families might have already accepted the possibility, after two decades, that their loved ones will never be identified. Families may also be too upset to get any remains back, Cain added.
"I would be happy for another family if I thought that would give them peace," Cain said. " I don’t know how other family members would feel about it."
In her case, Cain initially got back some of her son’s remains in late 2001 and buried them at St. Charles Cemetery in East Farmingdale. When Cain got a telephone call a year later informing her that another small piece of remains was identified, she recalled having a mixed reaction.
"I was glad to get it, but it just throws you right back to Sept. 11 all over again," recalled Cain. "But it was a tremendous sense of relief, we could lay him to rest."
The Massapequa mom she would welcome more of George's remains. "If there is the tiniest little morsel of my son, yes, I want him back. He belongs to me," Cain said.
Retired FDNY Deputy Chief Jim Riches, of Bay Ridge, lost his firefighter son Jimmy, 29, at One World Trade Center and over the next few months received some of his remains. Should NGS help discover more of Jimmy's remains, he would want to have them so they could be buried in the grave at St. John Cemetery in Middle Village, a place he visits often to say prayers and talk to his son.
"It is up to each family if they want to be notified or don’t want to be notified. I chose to be notified," Riches said.
One Long Island woman in Nassau County who lost her husband in One World Trade Center said she never received any of his remains and believes any new discovery from NGS would be a good thing.
"I am not opposed to it at all," she said, adding that a potential recovery would allow for a burial.
Efforts to identify victims slowed after 2019
Officials said that although about 1,600 of the 2,754 World Trade Center victims have been identified in the last 20 years, efforts to use conventional DNA technology to put names to the remaining fragments of humanity found at Ground Zero have slowed to a trickle, with the last official identification of a victim in 2019.
Experts said the catastrophic physical forces of the World Trade Center building collapses, as well as the resulting fires and chemical contamination, had made their genetic material unable to be analyzed with conventional methods.
Jonathan Kui, DNA lab supervisor at the OCME, said the new World Trade Center work will being carried out by staffers under Carl Gajewski, also a lab supervisor at the office.
Desire explained that the NGS system, which uses a special device the size of a large desktop printer, is so sensitive and advanced that it can be used to identify missing persons and crime victims. The new sequencing procedure also could be used for unidentified victims in the Gilgo Beach killings, he said.
The military began using NGS, also known as "massively parallel sequencing," in 2016. So far, the remains of hundreds of American soldiers who died in World War II and the Korean and Vietnam Wars have been identified, McMahon said.
Pandemic delayed implementation of new technique
The city's medical examiner began studying the process in 2018, but the coronavirus pandemic and other difficulties associated with COVID-19 slowed down the evaluation. But in February, Desire, Kui and a team of OCME officials presented the results of a study which validated the use of NGS to a state DNA subcommittee, which cleared the way for use of the technology.
Unlike more conventional methods, which focus on the DNA contained in the nucleus of cells, NGS digs into another form of genetic material found in cell mitochondria. The mitochondria are small bodies known as "organelles" found scattered around the inside of human cells and are believed to play a role in creating cellular energy.
While a human cell nucleus contains more than 3 million base pairs of four basic chemicals arranged in a double helix, each mitochondria contain just over 16,800 base pairs in circular fashion. An advantage to the mitochondria is that they are very numerous and increase the possibility that they are still intact within compromised forensic samples, said Anupama Gopalakrishnan, a senior official who deals with genetic identity products at Promega, a firm involved in NGS technology.
As explained by McMahon, analysts using NGS employ magnetic probes which are specific to the mitochondrial DNA and then amplify the results so they are above the thresholds needed for analysis to make an identification.
"An even better analogy would be taking five different cake batters, swirling them into one cake pan, being able to eat the cake and be able to discern the flavors, just by eating it," said Kui, adding that with NGS, as many as 30 samples can be processed at a time, compared with one under older methods.
In some cases, the DNA fragments have been so destroyed by World Trade Center fires that there is no possibility of retrieving any useful results with any technology, experts have noted.
More than 10,000 remains could potentially be subject to testing
Still, there are plenty of unidentified samples in the World Trade Center DNA repository which potentially could benefit from NGS analysis. About 10,000 unidentified remains, many small enough to fit in a test tube, would have to go through additional processing known as demineralization, in which bone fragments are ground with special equipment and treated, before they are subject to NGS analysis.
McMahon thinks the city will make good progress identifying remains once the process gets under way.
"Will it solve all cases? Probably not," McMahon said. "But even if it leads to 20 percent identification, that is significant. You are bringing closure to someone’s family on this."