Three retired firefighters died on Monday from 9/11-related injuries.

Fire Lieutenant Howard Bischoff and firefighters Robert Leaver and Daniel Heglund all worked at Ground Zero immediately following the 9/11 attacks.

Leaver and Heglund were childhood friends and grew up in the same Brooklyn neighborhood, according to James Lemonda, president of the Uniformed Fire Officers Association.

Fire Commissioner Daniel Nigro called their deaths “a painful reminder that 13 years later we continue to pay a terrible price for the department’s heroic efforts.”

One of the officers died of leukemia, one of esophageal cancer, and the third of colon cancer.

A variety of respiratory diseases and cancers are believed to be related to the inhalation of toxic air at Ground Zero. To date, 92 first responders have died from 9/11-related illnesses, and 850 people have been diagnosed with them.

At a press conference held Thursday, Lemonda urged Washington to renew the Zadroga Act, which provides medical care to first responders. The bill expires in 2016, and faced political opposition when it was first proposed in 2010. 

“This is not just a firefighters’ issue; this is an American issue,” said Lemonda. “We’re asking our elected officials in Washington to set aside their partisan politics, and I’m asking them to be as brave as the people who responded on that day.”

Ninety-nine percent of first responders have been diagnosed with a new respiratory illness since they served at Ground Zero.