PORTLAND, Maine (AP) — A Catholic Church in Portland has held a “Blue Mass” to honor first responders and those who’ve died in the line of duty.

WCSH-TV reports (http://on.wcsh6.com/1UO4BEm ) police, firefighters, and other public safety officers from across the state gathered at the Cathedral of the Immaculate Conception in Portland on Sunday.

The Bishop of the Diocese of Portland held the “Blue Mass,” which refers to the blue uniforms worn by many public safety personnel.

The tradition started in 1934. Public safety officers have scheduled it for the Sunday closest to Sept. 11 to honor those who died in the attacks. The Mass alternates locations every year in Maine, often between Lewiston and Portland.