Chlorides in caustic soda solution do not cause chloride SCC of austenitic stainless steels. A solution of 0.5 g/L NaOH at pH 12 is sufficiently alkaline to avoid this type of cracking that is common in neutral or acidic solutions. It has also been shown that chlorides inhibit caustic SCC. Mercury cell caustic typically contains 20 to 30 ppm chlorides, while diaphragm cell caustic is more likely to contain up to 1% chlorides. While chloride-contaminated caustic soda solution may not cause SCC of austenitic stainless steel if the caustic soda is consumed, for example, in a neutralizing process, the residual neutral chloride containing solution may then initiate cracking. This level of chlorides at 40C is unlikely to cause corrosion or cracking of carbon steel.