Several fire units responded to a residential structure fire in a mobile home  on Nathaniel St. in Mappsville  Saturday afternoon at approximately 2:45.   Units from Bloxom, Parksley, Atlantic, New Church and Tasley, Oak Hall Rescue and Sprint 2  responded to the blaze.  The structure  was fully involved when fire fighters reached the scene. No one was reported to be in the mobile home at the time of the fire.