Raymond J. Pfeifer, who spent eight months digging through the toxic debris of the collapsed World Trade Center for the remains of fellow firefighters and other victims and years lobbying, successfully, for health benefits for those who survived, died on Sunday in a hospice in Port Washington, N.Y. He was 59.

The cause was complications of cancers he contracted while searching the Lower Manhattan site after the 2001 terrorist attacks, his wife, Caryn, said.

“I’m being poisoned, and I’m dying, every single day, because of terrorism,” Mr. Pfeifer told WPIX-TV in 2014.

But unlike the 343 firefighters who died on Sept. 11, 2001, “I’m a very lucky man,” he said.

“My friends were murdered on 9/11,” he added. “From the 12th on, from that day on, I’m still here. I’m very lucky. I got to watch my kids grow up.”