Shortly after 2:00 p.m. today, several fire trucks arrived at the newspaper production building on West Boardman Street just west of Hazel Street. Hoses were seen attached to nearby hydrants. The building appeared to be evacuated. Workers were seen standing at the back of the building along West Front Street.
Vindy Fire no big deal
http://www.wfmj.com/story/22623990/fire-evacuates-newspapers-building
Most likely there was a buildup of paper dust in the air ducts of the press room.
During a press run there is a buildup of paper dust in the press bays, and when it is cleaned up, air hoses are used to clean off the presses which puts the dust into the air and vents.
What started the fire today could have been a spark in one of the air ducts.
It turned out that it was a spark that started the fire in the air handler while it was being maintained.