On November 12, 2008, a 2-million-gallon liquid fertilizer (UAN) tank (designated as Tank 201 by the owner) catastrophically failed.
On the day of the incident, X was filling Tank 201 with liquid fertilizer to check for leaks prior to painting the tank. During the filling, a welder and his helper sealed leaking rivets on the tank.
At a fill level about 3.5 inches below the calculated maximum liquid level, the tank split apart vertically, beginning at a defective weld located midway up the tank.
Two workers were seriously injured and partially flooding an adjacent residential neighborhood.
Within seconds, the liquid fertilizer overtopped the secondary containment, partially flooding the site and adjacent neighborhood. The collapsing tank wall injured the welder and his helper, who were working on the tank.
Employees of a neighboring business responded and extricated them.
At least 200,000 gallons of the liquid fertilizer were not recovered; some entered the southern branch of the Elizabeth River.
The CSB identified the following causes:
1. X did not ensure that welds on the plates to replace the vertical riveted joints met generally accepted industry quality standards for tank fabrication.
2. X had not performed post-welding inspection (spot radiography) required for the calculated maximum liquid level for the tank.
3. X had no safety procedures or policies for work on or around tanks that were being filled for the first time following major modifications and directed contractors to seal leaking rivets while Tank 201 was being filled to the calculated maximum liquid level for the first time.
The Lessons Learned:
The CSB makes recommendations to the U.S. Environmental Protection Agency, the Governor and Legislature of the Commonwealth of Virginia, X, Inc., HMT Inspection, Inc., and The Fertilizer Institute.
United States Environmental Protection Agency.
Revise and reissue the Chemical Emergency Preparedness and Prevention Office Rupture Hazard from Liquid Storage Tanks Chemical Safety Alert. At a minimum, revise the alert to
- Include the X tank failure,
- Discuss the increased rupture hazard during first fill or hydrostatic testing, and
- List The Fertilizer Institute fertilizer tank inspection guidelines in the reference section.
Governor and Legislature of the Commonwealth of Virginia
Require state regulation of 100,000-gallon and larger fertilizer storage tanks (which presently are located solely along and in the area of the Elizabeth River) or authorize local jurisdictions to regulate these tanks. The regulations should
- Address design, construction, maintenance, and inspection of 100,000-gallon and larger liquid fertilizer storage tanks, and
- Incorporate generally recognized and accepted good engineering practice.
Hire a qualified independent reviewer to verify that maximum liquid levels for all tanks at X’s Norfolk and Chesapeake terminals meet the requirements of American Petroleum Institute Standard 653, Tank Inspection, Repair, Alteration, and Reconstruction. At a minimum, the review should verify that all requirements for welding, inspection of welds, and In-Service and Out-of-Service tank inspections are met. Make the complete review report for both terminals available to the Cities of Norfolk, Chesapeake, and Portsmouth, Virginia, as well as the Virginia Department of Environmental Quality.
Develop and implement worker safety procedures for initial filling of tanks following major modification or change-in-service. At a minimum, require the exclusion of all personnel from secondary containment during the initial filling.
HMT Inspection, Inc.
Implement The Fertilizer Institute’s inspection guidelines as part of tank inspector training and inspection procedures for fertilizer tank inspection.
Revise company procedures to require tank inspectors to verify that radiography required as part of the calculation for a maximum liquid level has been performed.
The Fertilizer Institute
Formally recommend to all member companies the incorporation of The Fertilizer Institute tank inspection guidelines into contracts for the storage of liquid fertilizer at terminals.