Luis G. Alvarez, former New York City police detective and outspoken advocate for 9/11 responders died this week, after a three-year battle with cancer. He was 53, The New York Times reports.

His family announced his death in a Facebook post. The cause of death was complications from colorectal cancer. Doctors said his illness was linked to the three months he spent working at the site of the toppled World Trade Center searching for survivors and the bodies of fallen officers.

For years, Alvarez fought on behalf of emergency workers and thousands of survivors like him to extend health care protections for anyone who became sick after responding to the September 11, 2001, terrorist attacks in New York City. He was one of several advocates (including comedian and former Daily Show host Jon Stewart) to testify before Congress last month urging for a replenishment of the September 11th Victim Compensation Fund.

Alvarez’s death comes just as the House is expected to vote on whether to permanently extend the fund, which would offer health care to those affected. During his testimony, Alvarez said: “I will not stand by and watch as my friends with cancer from 9/11 like me are valued less than anyone else because of when they get sick. You made me come here the day before my 69th round of chemo. I’m going to make sure that you never forget to take care of the 9/11 responders.”

The next day, according to Alvarez’s family, he was too disoriented to receive treatment. Later, tests showed that his liver was failing. Within a week, he was admitted into a hospice in Rockville Centre, New York. He died last weekend. 

The September 11th Victim Compensation Fund is projected to be depleted by the end of 2020. So far, about 21,000 claimants have received nearly $5 billion in health care services. An additional 19,000 claims are pending.