Marci Simms, a lieutenant for the New York Police Department, died of lung cancer at her home on Long Island on Thursday, 14 years after she worked at for several months at ground zero after the 9/11 attacks.

Family members, friends and fellow officers paid tribute to Simms, 51, during her funeral service on Sunday. Relatives revealed that she was one of many people who helped with rescue, recovery and clean-work in the rubble, which made her ill, according to the Associated Press.

Simms was diagnosed with lung cancer in 2014, and her husband Keith stepped up to look after her. Her medical costs, meanwhile, were taken care of by the James Zadroga 9/11 Health and Compensation Act.

The act "ensures that those affected by 9/11 continue to receive monitoring and treatment services for 9/11-related health problems through at least 2015." U.S. President Barack Obama signed it into law in 2011, the Daily Mail U.K. reported.

"She was just a truly amazing human being - one in a million," said Simms' sister Susan Fosco, 63. "She was an angel. She was a saint. She was my hero."

After graduating from John Jay College of Criminal Justice, Simms joined the police department in August of 1998. She worked at Manhattan and Brooklyn precincts before joining the 107th Precinct in Flushing, Queens, in May 2013, the New York Daily News reported.