Two New York City firefighters have died on the same day due to 9/11-related illnesses.

Firefighter Richard Jones, 63, and Lt Paul Deo Jr, 74, both died on Friday from illnesses caused by their work at Ground Zero following the collapse of the Twin Towers on 9/11, FDNY Commissioner Daniel Nigro said in a statement.

”Nearly two decades later, our FDNY family continues to lose remarkable men and women who never wavered in their commitment to protecting life and property in our city," Mr Nigro said. "Our department will never forget them or the bravery they exuded throughout their careers.”

Mr Jones spent his 20-year career with the FDNY by working for Ladder 25, an Upper West Side-based company that lost seven firefighters after the South Tower collapsed. He was awarded three acts of merit between the years 1992 and 1997, which is given to firefighters who go above and beyond the call of duty.

Mr Deo, a Vietnam veteran and Marine, retired from Engine 317 in St Albans, Queens, after working for the department for 33 years. He was promoted to lieutenant in 1990.

Unseen 9/11 pictures show Ground Zero in wake of attacks Show all 30 1 /30 Unseen 9/11 pictures show Ground Zero in wake of attacks Unseen 9/11 pictures show Ground Zero in wake of attacks Thousands of photographs taken at Ground Zero in the wake of the 9/11 attacks have come to light after they were purchased at an estate auction. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks The photographs were shot among the rubble of the World Trade Centre towers during the clean-up operation between September and October 2001. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Unseen by the public since 2001, the pictures have emerged as they were bought by an archivist couple at the auction of a private estate. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks “My significant other acquired them at an estate sale as we collect & archive vintage media for public benefit,” says Dr Johnathan Burgess. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks The 2389 pictures were held on five CDs which Dr Burgess passed along to fellow archivist Jason Scott, who uploaded them to his Flickr page. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks The photographer behind the pictures is unknown but Dr Burgess and Scott are working to identify them. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks The Winter Garden Atrium is seen covered in debris. The building is nearby to the site of the former World Trade Centre buildings and was badly damaged when they collapsed. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks The steel frames of a World Trade Centre tower are seen following the attack that led to the building's collapse. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks The steel frames of a World Trade Centre tower are sprayed with water as part of the clean-up operation following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks The steel frames of a World Trade Centre tower are seen following the attack that led to the building's collapse. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks The Winter Garden Atrium is seen covered in debris. The building is nearby to the site of the former World Trade Centre buildings and was badly damaged when they collapsed. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to demolish the remaining sections of building left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks The Winter Garden Atrium is seen covered in debris. The building is nearby to the site of the former World Trade Centre buildings and was badly damaged when they collapsed. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Clouds of dust rise as contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks A tribute message is hung above a US flag on the AmEx tower which was damaged in the collapse of the nearby World Trade Centre towers following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors take a break during the clean-up operation following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Dust rises as contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott Unseen 9/11 pictures show Ground Zero in wake of attacks Contractors work to clear the debris left after the World Trade Centre towers collapsed following the 9/11 attacks. Jason Scott

Both firefighters were two of thousands of people who worked at Ground Zero in the aftermath of 9/11 to locate survivors and victims in the debris from the World Trade Center. They then both retired one year later within the span of one month of each other.

In 2016, Mr Deo was diagnosed with pulmonary fibrosis, a lung disease that occurs when the tissue is damaged or scarred, and received a lung transplant last year.

Funerals for the two men will be held at Saint Joseph’s Church in Manhattan later this week.

In total, more than 340 firefighters were killed at Ground Zero from the terrorist attack. Another 218 have since died from illnesses they suffered relating to the debris and air at Ground Zero, a number that has grown dramatically in recent years.

A study published in the Journal of the National Cancer Institute last month found workers exposed to the air at Ground Zero have a higher risk to contract specific types of cancer, such as leukaemia and prostate cancer.