Free-cutting leaded brass is commonly used as sleeve fittings (also termed clamping ferrules) on polytetrafluoroethylene-lined flexible hoses for the filling and distribution of compressed gases, e.g., oxygen, nitrogen and carbon dioxide, for various industrial and medical applications. Some of the gas-filling and gas distribution facilities are located in the proximity of highly industrialized areas for the convenience of transportation, application and customer service. Therefore, the gas-filling and gas distribution gears are frequently exposed to the environment containing various chemical substances, which in the presence of ambient moisture and under the influence of mechanical and residual stresses in the material can effect an undesirable material degradation reaction. Stress corrosion cracking (SCC) has been identified to occur in C36000 Cu-Zn-Pb leaded brass ferrules under the synergistic reactions of a sulphuric acid production environment in a sustained tensile stress environment. The tensile stress was imparted to the material by the mechanical crimping process applied on the ferrules, and superimposed by cyclical high-pressure gas-cylinder-filling operations. The chemical species responsible for the SCC originated from the gaseous vapours and/or ionic derivatives of S-containing substances emitted from a neighbouring sulphuric acid production plant, which reacted with water and moisture condensates on the brass ferrule surfaces and effected the chemical corrosion reaction(s). SCC of the leaded brass ferrules gave rise to predominantly intergranular failures with fracture surfaces heavily decorated by corrosion products of various configurations. Most corrosion products were found to have embedded on the grain-boundary planes of the fracture surfaces, suggesting that grain-boundary short-circuit diffusion may have served as a viable mechanism for the SCC of C36000 leaded brass under the operating conditions of this case study.