BALTIMORE (WJZ) — For the first time in more than two centuries, the entire Baltimore City Fire Department is out of service on Wednesday.

The Maryland Department of Emergency Management is working with agencies statewide to fill in so that every member of the city fire department could attend a memorial service for three fallen firefighters.

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It marks the only time in the fire department’s 225-year history that all of its members have been sidelined, the agency tweeted.

As many as 15,000 to 20,000 firefighters, including those traveling from across the country, were expected to be in attendance for the memorial.

They were among thousands, including Mayor Brandon Scott and Gov. Larry Hogan, who gathered Wednesday at the Baltimore Convention Center to pay their final respects to three Baltimore firefighters who made the ultimate sacrifice last week.

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Lt. Paul Butrim, Lt. Kelsey Sadler and Kenny Lacayo died in the line of duty Jan. 24 after a partial collapse trapped them in a burning, vacant home in West Baltimore, a tragedy that has sparked a new campaign to address the city’s vacancy problem.

A fourth firefighter caught in the collapse, John McMaster, was rescued from the rubble and survived. He was released from Shock Trauma three days later.

The memorial service was held at the convention center. From the convention center, the late firefighters’ bodies were escorted to Dulaney Valley Memorial Gardens, a 70-acre cemetery in Timonium.

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If you would like to help the families of these fallen heroes, the Baltimore City Fire Foundation is accepting donations on their behalf. The foundation routinely raises money for the families of firefighters who are injured or killed in the line of duty.

CBS Baltimore Staff