At 1221 hours Station 2 was alerted mutual aid to St. Mary’s County, Co.’s 2 area, for the working house fire in the area of Miles Dotson Rd. Engine 23 and Tanker 2 responded immediately from dispatch. Mechanicsville’s Engine 224 arrived on the scene and reported a working RV Trailer fire and shortly after Engine 23 arrived picking up E-224’s supply line. Command, Chief 2 Railey, held units on the scene and Tanker 2 placing the rest of the assignment in service. Units operated for just over an hour with the camper being a total loss.