Austenitic stainless steel is a major construction material for urea plants. Since 1986, we have been faced several failures of austenitic stainless steel piping and vessels. In this article five cases of failure are reported . Investigations show that all cracks started from outside (non process side) under the insulation and the reason of failure is stress corrosion cracking (SCC) due to concentration of chloride in insulation which is impregnated in the prevailing (marine) environment of the site.