Cytec's ammonia storage tank was last inspected in 1989, and based on internal requirements, would have been due for an internal inspection in 1999. Cytec has only one atmospheric ammonia storage tank. Inspecting this single tank would require solving significant logistical problems to avoid major business disruptions to the downstream operating units, Additionaily, we wished to avoid the cost to decommission and clean, dispose of the wastes generated, inspect, and re-commission the tank. Based on prior inspection reports and a risk-based inspection documented by Capstone Engineering, the tank has been approved for at least five more years of service without an internal inspection. Within five years, an acoustic emission study will be conducted to insure that no audible defects can be found.