A 56-year-old Iowa woman was killed in an explosion at a gender reveal party after family members “inadvertently” created a pipe bomb, according to authorities.  The victim was identified as Pamela Kreimeyer by the Marion County Sheriff’s Office on Monday. She was killed instantly the day before when she was struck in the head by a metal piece that had been sent flying in the explosion at the Knoxville home. Advertisement  The sheriff’s office indicated that the family had been experimenting with different types of explosive material in the days leading up to the tragic accident. They ended up placing gunpowder in the bottom of a “homemade stand” that was welded to a metal-base plate.  “A hole had been drilled in the side for a fuse, a piece of wood was placed on top of the gunpowder and colored powder was placed on top of the board,” the sheriff’s office said. “Tape was then wrapped over the top of the metal tubing, inadvertently creating a pipe bomb.” Kreimeyer was standing with other family members about 45 feet from the device when she was killed. The sheriff’s office said the projectile that struck Kreimeyer may have continued to travel another 140 yards through the air before coming to rest in a field.  An investigation is ongoing.  “This is a reminder that anytime someone mixes these things there is a high potential for serious injury or death; please do not take these unnecessary risks,” Sheriff Jason Sandholdt said in a statement. “My condolences go out to the family.”