This lab is still trying to identify 9/11 victims. Not everyone wants to knowSeptember 10|Duration 10:5225 years after the September 11 attacks, a team of forensic experts continues the monumental task of identifying remains from the World Trade Center debris. CBC News chief correspondent Adrienne Arsenault goes inside the lab using cutting-edge DNA science to bring closure to families — and explores the difficult reality that not everyone wants to know.Inside a lab in Manhattan, forensic scientists in white lab coats are still diligently working to keep a promise made 25 years ago.They're extracting DNA from thousands of pieces of human remains recovered following the terrorist attacks on the World Trade Center, trying to match them to samples from toothbrushes, razors and other sources provided by family members of victims.What has changed is the science they're using to draw out the DNA from the remains, and the evolving forensic investigative techniques that didn't exist in 2001."When … after years of pushing that science, you're finally able to figure out who it is and return that loved one to their family … that's powerful," said Mark Desire, assistant director of forensic biology at the New York City Office of the Chief Medical Examiner. Forty per cent of the 2,753 people who died at Ground Zero have not had their remains identified, including approximately 10 of the 24 Canadian victims.Last month, the lab announced it made its first identification of previously unknown remains using a breakthrough technique. The woman's family chose to keep her name private. It's the first identification the lab has made in a year.WATCH | Special live coverage from New York City on the 25th anniversary of 9/11:9/11: 25 years later | Live from Ground ZeroCOMING UPIn 3 hoursThe CBC's Adrienne Arsenault and Paul Hunter host special coverage from New York City of the 25th anniversary for the Sept. 11 terrorist attacks. Victims' families and former U.S. presidents are expected to attend a memorial ceremony at Ground Zero.