OCME says DNA limits leave roughly 1,100 9/11 victims unidentified
Fire, water, chemicals and years of exposure have degraded DNA from remains recovered at Ground Zero, officials say; three more victims identified using improved testing.
The New York City Office of the Chief Medical Examiner (OCME) said Thursday that approximately 1,100 people who were at the World Trade Center on Sept. 11, 2001, remain unconfirmed because investigators lack sufficient DNA evidence to make definitive identifications.
OCME officials said the remains recovered at Ground Zero and during subsequent searches have been so extensively degraded by fire, water, sunlight, chemicals and other factors that many samples no longer contain viable genetic material for comparison to relatives. The agency announced three recent identifications made possible by improved testing, bringing the total number of identified victims to 1,653.
Dr. Jason Graham, New York City’s chief medical examiner, said in a statement that the office remains committed to identifying the missing and returning remains to their families. "Nearly 25 years after the disaster at the World Trade Center, our commitment to identify the missing and return them to their loved ones stands as strong as ever," he said.
OCME officials and forensic scientists point to a combination of factors that make identification difficult. Mark Desire, the agency’s assistant director of forensic biology, told National Public Radio that extreme heat from the fires, the large volumes of water used to extinguish flames, sunlight, mold, bacteria, insects, jet fuel, diesel and building chemicals all can destroy or fragment DNA. "All these things destroy DNA," he said.
Investigators recovered remains from the North and South Towers, surrounding buildings and from debris sorted at the Fresh Kills landfill on Staten Island, where about 1.5 million tons of wreckage were taken by truck and barge in the weeks after the attacks. A 2011 study published in BMC Public Health said the sifting and sorting effort on Staten Island recovered 4,257 fragments of human remains and about 54,000 personal items.
OCME still maintains a secure repository at the bedrock level of the Ground Zero site where more than 8,000 unidentified bone fragments and tissue samples are stored and periodically reexamined as laboratory methods advance. The agency said it continues to reanalyze previously tested samples when new techniques become available.
The office announced three recent identifications in August. They included Ryan Fitzgerald, 26, of Floral Park, New York; Barbara Keating, 72, of Palm Springs, California; and a woman whose family asked to remain anonymous. The agency credited improvements in DNA analysis for making those matches possible.
Not all observers are confident that all remaining victims can ever be identified. A former New York Police Department officer who took part in recovery work and spoke to the Daily Mail on condition of anonymity said the scale and duration of the recovery effort, and the fact that thousands of rescuers and recovery workers operated in and around smoldering debris for months, likely contaminated many scenes and displaced tiny biological traces beyond the possibility of future detection.
The logistics of the recovery and handling of debris have also complicated later efforts. Debris was moved to Fresh Kills and was not preserved in sterile conditions; construction work at the redeveloped World Trade Center site has uncovered additional truckloads of material that may contain human remains. In 2013, workers discovered about 60 truckloads of debris during construction of part of the new site, roughly 11 years after the primary sorting at Fresh Kills ended in 2002.
OCME officials have said they rely on incremental advances in forensic science to make additional identifications. Desire said laboratories have repeatedly returned to samples that earlier produced no usable DNA and have been able to extract results as methods improved. He added the office remains hopeful that future technological breakthroughs will allow more matches, but he also acknowledged the limits posed by the condition of many samples.
Across the World Trade Center attacks, about 2,753 people were killed in New York City when hijacked airliners struck the Twin Towers. The OCME’s current tally of 1,653 confirmed identifications leaves roughly 1,100 people whose remains have not been matched to family members. The agency said it will continue to analyze samples and pursue identification as long as technology allows, while preserving the repository of fragments for possible future testing.