A structure fire Friday afternoon in rural Great Bend was caused by a butane explosion in what law enforcement officers are calling a clandestine lab manufacturing “marijuana wax,” also called BHO or DAB.Sheriff Brian Bellendir said the Barton County Sheriff’s Office and Great Bend Fire Department were dispatched to the 70 block of SE 20 Road at 5:11 p.m. on Friday for a possible structure fire and during the subsequent investigation it became apparent there had been a butane explosion.According to a press release issued Monday, the resident had fled from the area. He later returned to the scene with severe burns but refused medical treatment. Bellendir declined to name the resident and said no arrests have been reported at this time.