Club Valiants Inc., an organization of black firefighters, recently settled a lawsuit with the city that charged white firefighters with making racist Internet postings while on duty and from city computers.
The black firefighters also have complained that Local 22, whose leadership is primarily white, has become "a hostile, anti-minority, and offensive union for African American firefighters."
Gillison said that despite those fissures, firefighters suspend their differences on the job.
"They bring who they are to work, but I can tell you they work together well on the fire ground," he said. "Professionalism usually will trump racial issues."