The Fire Department of New York says the number of its members who have died from 9/11-related illnesses is now equal to the number lost on the day of the attacks, 343.
Two recent deaths added to the toll.
“With these deaths, we have reached a sombre, remarkable milestone,” New York City Fire Commissioner Laura Kavanagh said in a statement.
“Our hearts break for the families of these members, and all who loved them.”
Soon after the 22nd anniversary of the attacks, emergency medical technician Hilda Vannata died on 20 September from cancer, while retired firefighter Robert Fulco died of pulmonary fibrosis on 23 September, according to city officials.
Both illnesses were a “result of time they spent working in the rescue and recovery at the World Trade Center site,” the New York City Fire Department said in a statement.
Nearly 3,000 people were killed in the 11 September attacks in 2001, with most of the deaths in New York. There, Al-Qaeda militants crashed two US passenger jets they had seized into the twin towers of the World Trade Center.