Recommendation FLIX-212: Alert industry to nitrate stress corrosion risk from contaminated cooling water

The cracked Reactor R2525 initiated the sequence of events which led to disaster. Examination of the crack by expert metallurgists showed that the crack had been caused by nitrate stress corrosion. This corrosion was created because nitrate treated cooling water had been used in the past to dilute small leakages of cyclohexane from the plant. This phenomenon had not been appreciated by the management at the time the water was used and may not even yet be appreciated by other sectors of the chemical industry. Where such cooling water is used the vessels and piping should be adequately protected. The attention of industry should be drawn to the risk.