Suspicious fires by Occupancy
At least 53% OF Structure FIRES WERE SUSPICIOUS OR Likely Caused by arson
To determine if a fire was suspicious in nature or arson, we used the disposition codes given by firefighters at the scene. 50% of fires have disposition codes of 021, or "suspicious." 3% of fires were disposition 011, or "incendiary."
These numbers are an estimate, as the disposition code is a preliminary assessment made by firefighters at the scene. The actual number of suspicious fires changes after further investigation by the Fire Investigation Division. The city does not provide fire cause information in its open data portal:
"The release of 'Cause of Ignition' information may aid in the performance of criminal activity and may jeopardize certain facets of investigations performed by the Detroit Fire Department Arson Investigators. Accordingly, the column has been removed."
How arson is investigated
The Fire Investigation Division’s task is investigating fires in the City of Detroit. Arson investigators respond to suspicious fires 24 hours a day, seven days a week. The investigators, part of a joint unit located under the Detroit Fire Department and Detroit Police Department, focus on identifying the cause of fires and conducting criminal investigations into the fires.
Over the course of 2015, the Fire Investigation Division investigated 1,585 incidents, including structures, garages, vehicles, and other types of fires.
The Detroit Fire Department provided the following data about fires that were investigated:
DFD Fire Investigations by Structure in 2015
DFD 2015 Investigation Totals by Code of Interest
256 STRUCTURES HAD MORE THAN ONE FIRE OVER THE COURSE OF THE YEAR.
Repeat Fires by Inital Cause
Additional Fires by Cause
Many structures burned more than once in 2015. Our survey found that 67% of initial fires were suspicious in nature, 14% higher than the overall arson rate.
The leading cause of additional fires was arson, followed closely by "rekindles."
Rekindles occur when a previously extinguished fire reignites. Most rekindles are minor in nature, and are quickly extinguished. The survey only covered rekindles that were severe enough to cause additional damage to the structure.