Construction crews have avoided a potentially dangerous situation after some equipment caught on fire.  The Washington County Safety Center reported the fire just after 2:15 p.m. Thursday at a construction site just north of Marr Park near Ainsworth.  Workers had been clearing brush in the area before a scraper belonging to Townsend Excavating of Wellman caught fire due to an electrical problem.  The Washington Fire Department and Ainsworth Fire Department responded to the scene to assist in putting the fire out, as workers only had one fire extinguisher to use.   No injuries have been reported.