In most cases these shafts are not in use, but they still may contain heavy objects not substantially secured that may fall through the shaft, such as pulleys, mechanisms, etc..5.0 OPERATIONAL TECHNIQUES AND USE OF TOOLS5.1 ROOF HAZARDS??? Open shafts ??? Low or no parapet wall??? Soil pipes ??? TV and radio antennas??? Clotheslines ??? Sloping roofs??? Sloping cornices ??? High bulkheads??? Walk