LANCASTER – Police are investigating a fire set outside the Lancaster City Visitor’s Center at Penn Square on Sunday around 3 a.m. Arriving units found the fire was spreading to the building. Fire personnel quickly extinguished the blaze which began in a portable toilet, located outside the building. The fire grew large enough to cause some structural damage and damage to the windows. It also caused the building to fill with smoke. There were no reported injuries. Damage estimates are unknown at this point. Investigators were checking the area for surveillance cameras and are reviewing video footage to attempt to identify those involved. Anyone with information related to the incident is urged to call Lancaster City Police at 717-735-3300 or Lancaster City-County Crime Stoppers toll free at 1-800-322-1913.