Blitz Week was a period of United States Army Air Forces (USAAF) aerial bombardment during the 1943 Combined Bomber Offensive of World War II. Air raids were conducted on six of seven days as part of Operation Gomorrah, against targets such as the chemical plant at Herøya, Norway, which produced nitrates for explosives; and the AGO Flugzeugwerke AG plant (an Operation Pointblank target) at Oschersleben, Germany that assembled Focke-Wulf 190s. The Kassel mission on July 28, 1943, was the first use of P-47 Thunderbolt auxiliary fuel tanks.