Hundreds of mourners gathered at the First Reformed Church of Nyack Thursday to remember David Jahnes, the firefighter who had a heart attack last week while responding to reports of a chemical spill at a bank.

The 58-year-old was a 16-year veteran of the Nyack Fire Department, and he spent a lot of time in its marine unit.

"This was a line of duty death," says Nyack Fire Chief John Galietta. "That touches us particularly, because that is the one thing that we all worry about and work not to have happen."

"I've seen the fire department work hand in hand with law enforcement, and to lose one of our own...is a tragedy," says Rockland County Executive Ed Day, a former NYPD first responder himself. "They protect this community every day, without regard to their own health or well-being."

Jahnes was also a member of the Nyack Fire Patrol and served as captain from 2008 to 2011.

"It's hard to find the words to describe the person he was," says Linda Schultz, a friend. "He was always there for everyone, besides being an incredible volunteer fireman. He was there to help people, always."