The attacked areas were all in the weld or in close vicinity of the welds. These were covered with reddish brown deposits, and the investigations showed that the weld quality was poor. Remains of root paste could be seen, which has been used to form a slag layer on the root side of the weld to protect the weld root from oxidation. The weld itself was partly corroded, but pits were also present in the heat affected zone. High amounts of manganese, chromium, iron, and smaller amounts of sulphur, phosphorus, and chlorine were found by EDS in deposits covering the pits. Bacteria were detected in the failure area with a total aerobic count of 7.8*103-1.4*104 cfu/ml and SRB 54 cfu/ml.