The death of two small children in a house in Germany’s Lower Franconia region is being attributed to phosphine gas poisoning caused by negligent use of a pesticide, police and prosecutors said on Thursday. The children, a 5-year-old girl and her 4-year-old brother, were found by their brother in their house in Karlstein am Main, a small town in the north-west of Bavaria, on Monday morning. Their father admitted to police that he had used a pesticide during work on the house. Police are working on the assumption that possible inappropriate use of the pesticide led to a chemical reaction in whi…