The decommissioning of the Strontium Semiworks Complex, located in the 200 East Area of the Hanford Site, is nearing completion. This facility operated as a pilot plant from 1949 to 1967 to develop fuel reprocessing technology and a method for separating strontium from high-level liquid wastes. Contamination of the facility from these operations was extensive. One of the major activities completed was the decommissioning of the plant exhaust stack. Demolition of the stack was accomplished using explosives. This required decontamination of the stack interior to minimize the release of airborne contamination. Radiation levels in the stack prior to cleaning ranged from 2.5 to 90 mGy/h as measured along the stack centerline. Decontamination was accomplished by sandblasting, using equipment specially designed and fabricated to allow the work to be performed remotely. Radiation levels measured after decontamination were in the range of 0.01 mGy/h. No airborne contaminants were detected following the demolition using air samplers stationed along the perimeter of the site.