Janesville firefighters work into the early morning hours Wednesday fighting a fire at the city’s landfill.  Firefighters say they could see a glow from Blackbridge Road while on route to the fire about 11:00 p.m. Tuesday.  One engine, two tankers, and two brush trucks were used in extinguishing the fire on the landfill’s north side.  The Milton Fire Department also assisted.  Firefighters spent four-and-a-half hours on the scene.  No cause has been officially announced, but firefighters say this type of event can occur as part of normal decomposition process.