Firefighters from six area fire departments responded to a smoky fire shortly after 1:30 a.m. Dec. 25, 2018, in the 700 block of Walnut Street, Emmaus.

Dense smoke was pouring from the structure, causing first-arriving Emmaus firefighters to declare a second alarm to request mutual aid. Firefighters from Western Salisbury, Vera Cruz, Lower Macungie, Alburtis and the Woodlawn fire departments responded.

The structure was an office building that did not appear to be currently occupied. A bystander identifying himself as the building’s owner said it had been “several months” since anyone had worked in the office.

Firefighters said the fire was centered in the basement of the building which contained boxes of paper files. The cause of the fire appeared to be electrical in origin.

Crews from Emmaus and Macungie Ambulance Corps provided standby and rehab services for the firefighters working in their heavy protective gear.

Firefighters from the Alburtis Fire Department Rapid Intervention Team, without active firefighting responsibilities, stood by to render assistance to any interior firefighters that might have gotten into trouble.

Woodlawn Fire Department’s air cascade truck replenished depleted air tanks for the firefighters working inside the building.