Luis G. Alvarez, a former New York City detective who pleaded with Congress this month to extend health benefits to police officers, firefighters and other emergency workers who responded to the Sept. 11, 2001, terrorist attacks, died on Saturday in a hospice in Rockville Centre, N.Y. He was 53.

His family announced his death in a post on Facebook. The cause was complications of colorectal cancer, for which Mr. Alvarez received a diagnosis in 2016. The disease was linked to the three months he had spent at the site of the toppled World Trade Center towers in Lower Manhattan, searching for survivors and for remains of his fellow officers on nearby rooftops and in the toxic rubble at ground zero.

Mr. Alvarez, the father of three sons, including two teenagers, delivered a raspy appeal before a House Judiciary subcommittee in Washington on June 11 to replenish the September 11th Victim Compensation Fund.

He appeared alongside Jon Stewart, the former host of “The Daily Show,” who delivered a passionate call for justice on behalf of the victims.