An early-morning fire last Wednesday on the exterior of an apartment building on the west side of the city could have been much worse if not for a sprinkler system, Champaign Fire Department Battalion Chief Tyler Funk said Thursday. Firefighters were called to 1313 Mariner Way around 4:30 a.m. when a deck fire set off a sprinkler and an alarm. Funk said the sprinkler mostly controlled the fire. The occupants were sleeping. Other than some melted siding, Funk said, there was no smoke or fire damage to the interior. There were no injuries and no residents will be displaced. The cause of the fire remains under investigation.