Excluded from the definition of accident are "depletion, deterioration, corrosion, and erosion; wear and tear; leakage of any valve, fitting, shaft seal, gland packing, joint, or connection; breakdown of any vacuum tube, gas tube, or brush; breakdown of any electronic computer or electronic data processing equipment; breakdown of any structure or foundation supporting the "object" or any of its parts; and the functioning of any safety or protective device."