In addition to minimizing potential for safety hazards associated with the presence of flammable mixtures inside the tanks, it is also desirable to install gas blanketting to prevent air ingress and associated corrosion and compliance with sales gas specs, when tanks are connected to a vapor recovery system. In several applications where water tanks are not connected to a gas blanketting system (i.e., using fuel gas) severe corrosion has been found in the water injection system. In amine unit when tanks do not have blanket gas, Heat Stable Salts are formed causing severe corrosion. In summary, gas blanketting requirements are driving by safety considerations, corrosion issues, and potential for degradation of stored chemicals. To my knowledge, there is not a specific US regulation that forces the use of gas blanketting.