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Safety Recommendation Details

Safety Recommendation H-04-023
Details
Synopsis: About 11:50 a.m. central daylight time on April 15, 2003, a nonspecification cargo tank used by River Valley Cooperative (River Valley) exclusively for agricultural purposes as a nurse tank split open after being filled with anhydrous ammonia at River Valley’s nurse tank filling facility near Calamus, Iowa. About 1,300 gallons of the poisonous and corrosive gas escaped, seriously injuring two nurse tank loaders, one of whom died from his injuries 9 days after the accident. The National Transportation Safety Board determined that the probable cause of the accident was inadequate welding and insufficient radiographic inspection during the tank’s manufacture and lack of periodic testing during its service life.
Recommendation: TO THE PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION (ORIGINALLY ISSUED TO RSPA): Require periodic nondestructive testing to be conducted on nurse tanks to identify material flaws that could develop and grow during a tank’s service and result in a tank failure.
Original recommendation transmittal letter: PDF
Overall Status: Open - Unacceptable Response
Mode: Highway
Location: Calamus, IA, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA03MZ001
Accident Reports: ​Nurse Tank Failure with Release of Hazardous Materials
Report #: HZM-04-01
Accident Date: 4/15/2003
Issue Date: 7/1/2004
Date Closed:
Addressee(s) and Addressee Status: PHMSA (Open - Unacceptable Response)
Keyword(s): Hazmat

Safety Recommendation History
From: PHMSA
To: NTSB
Date: 2/26/2019
Response: -From Howard R. Elliott, Administrator: The Federal Motor Carrier Safety Administration (FMCSA) continues to research nurse tank safety and is currently in Phase IV of its Refine Non-Destructive Testing to Improve Nurse Tank Safety Study. Phase IV of the study seeks to refine recommendations for non-destructive testing of nurse tanks by exploring the use of multi-phase ultrasonic examination as a nondestructive examination method. Phase IV will also use acoustic emission testing to determine if hydrostatic pressure testing exacerbates existing stress corrosion cracks (SCCs). In accordance with the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180), nurse tanks without data plates must undergo. hydrostatic pressure testing every 5 years. Some agricultural cooperatives also perform hydrostatic pressure tests on nurse tanks with data plates. In Phase 111 of the study, the FMCSA research team revisited previously examined nurse tanks to better determine the rate of propagation of the detected cracks over time and to identify the initiation of new cracks in relation to the causal factors associated with SCCs. In July 2018, the FMCSA published a final report on Phase III, which identified that limitations to the resolution of the single-beam ultrasonic examination method could prevent the examiner from determining whether indications found parallel to the weld during examination are cracks in the nurse tank or a feature of the weld. Building upon this research, Phase IV of the study is now examining whether phased array ultrasonic examination may resolve this limitation. Although research is ongoing, the preliminary results from Phases I through III of the study have identified a manufacturing process that could largely eliminate the formation of secs in new nurse tanks. Nurse tanks examined in the study that underwent post-weld heat treatment (PWHT) showed significantly fewer SCCs than nurse tanks that did not receive PWHT. PWHT reduces the stress in the metal around the weld areas, preventing the initiation of SCCs. Based on this information, PHMSA may consider proposing to require PWHT for all newly constructed nurse tanks in an upcoming rulemaking action. PHMSA will continue to provide NTSB with updates on FMCSA's progress. PHMSA plans to review the findings of Phase IV in conjunction with FMCSA to determine whether additional revisions to the nurse tank requirements in the HMR should be made. If we can be of further assistance, please do not hesitate to contact Dirk DerKinderen, NTSB Program Manager for the Office of Hazardous Materials Safety.

From: NTSB
To: PHMSA
Date: 6/22/2017
Response: We note that you and your sister agency, the Federal Motor Carrier Safety Administration (FMCSA), continue to conduct research to better understand and identify nurse tank material flaws. In addition, we note that the FMCSA plans to further research the viability of acoustic emission testing. Although we are pleased by the thoroughness of your research, we are concerned that, 13 years after this recommendation was issued, you have not yet developed a testing requirement. We urge you to expedite your efforts to develop and require nondestructive testing for nurse tanks, as recommended. Due to the age of this recommendation and lack of implementation progress, Safety Recommendation H-04-23 is classified OPEN--UNACCEPTABLE RESPONSE.

From: PHMSA
To: NTSB
Date: 5/5/2017
Response: -From Howard W. McMillan, Acting Deputy Administrator: The Federal Motor Carrier Safety Administration (FMCSA) continues to research nurse tank safety and is currently in Phase III of its Refine Non-Destructive Testing to Improve Nurse Tank Safety Study. The study sought to refine the recommendations for non-destructive testing of nurse tanks. The research team revisited previously measured nurse tanks to better determine the rate of propagation of the detected cracks over time and identify the initiation of new cracks (in relation to the causal factors associated with stress corrosion cracks). FMCSA plans to publish the final report of its findings in spring 2017. Additionally, FMCSA plans to request funding for a small follow-up project to explore the viability of acoustic emission testing in detecting cracking that occurs during use. PHMSA will continue to provide NTSB with updates on FMCSA's progress and plans to review the findings to determine whether revisions to the Hazardous Materials Regulations (HMR, 49 CFR Parts 171-:180) should be made.

From: NTSB
To: PHMSA
Date: 2/6/2012
Response: The NTSB notes that PHMSA published a final rule on February 1, 2011, amending the Hazardous Materials Regulations by incorporating provisions contained in certain cargo tank special permits, including a permit addressing nurse tanks. While this rulemaking is intended for only a specific group of nurse tanks—those with missing or illegible ASME plates—we applaud PHMSA’s continued efforts to address nurse tank safety. PHMSA indicated that the Federal Motor Carrier Safety Administration is also conducting research on nurse tank safety. We encourage PHMSA to monitor the research progress and update the NTSB with any new findings. In the meantime, pending the issuance of a requirement that periodic nondestructive testing be conducted on all nurse tanks, Safety Recommendation H-04-23 remains classified OPEN—ACCEPTABLE RESPONSE.

From: PHMSA
To: NTSB
Date: 4/4/2011
Response: CC# 20110149: - From Cynthia L. Quarterman, Administrator: I appreciate the effort you have made in the area of hazardous material and pipeline safety transportation. We share an interest in taking strong actions to continually improve the safe transportation of these materials throughout our country. In that regard, I have been meeting with the Pipeline and Hazardous Materials Safety Administration (PHMSA)'s hazardous materials and pipeline safety programs to assess our actions on the NTSB recommendations in the last six months. My goal is to continually address your safety recommendations by taking actions to assure that the "unacceptable actions" are moved into the "open-acceptable" category and to achieve a "closed-acceptable" in a timely manner on as many recommendations as possible. I recognize that a number of "open-acceptable" recommendations are works in progress and may take a year or more to complete. In the last six months you have issued four "Closed-Acceptable Action" classifications for the following recommendations: P-04-02, P-07-07, P-07-08 and P-10-01. In an effort to continue this progress, I have asked our hazardous material and pipeline staff to compile outstanding letters to the NTSB that request a change in the classification of a recommendation. I have enclosed a copy of the PHMSA letters requesting that the following five recommendations be classified as "Closed-Acceptable Action": A-07-107, A-07-108, R-07-05, A-08-01, and A-08-02. I am hopeful that you will review these letters and close the recommendations if you believe we have been responsive. In addition, I ask that you review NTSB Recommendation H-04-23 requiring that periodic nondestructive testing be conducted on nurse tanks to identify material flaws that could result in a failure. PHMSA published a final rule on February 1, 2011, requiring inspection and nondestructive testing to allow continued use of nurse tanks with missing or illegible ASME plates. I have enclosed a copy of the Final Rule as published in the Federal Register. In addition, our sister agency, the Federal Motor Carrier Safety Administration contracted with Virginia Polytechnic Institute to research nurse tank safety. If you have questions regarding any of these recommendations, please do not hesitate to call. Together, we are making a positive difference in the safe transportation of hazardous materials, including those transported by pipelines.

From: NTSB
To: PHMSA
Date: 9/4/2008
Response: The Safety Board notes that PHMSA is working with industry to study alternatives for specific measures to improve the safety of nurse tanks, including the costs and benefits of such measures. At a June 6, 2007, meeting with the Fertilizer Institute, PHMSA discussed the industry’s experience with the inspection program required by the special permit and the development of an industry standard for maintaining nurse tanks, including periodic testing and inspections. The Board further notes that PHMSA plans to hold additional meetings with its stakeholders as it continues to evaluate alternatives for enhancing nurse tank safety. Safety Recommendation H-04-23 remains classified OPEN -- ACCEPTABLE RESPONSE pending a requirement for periodic nondestructive testing to be conducted on nurse tanks to prevent tank failure. We would appreciate being informed of a timeframe for completing these efforts.

From: PHMSA
To: NTSB
Date: 7/31/2007
Response: Letter Mail Controlled 8/8/2007 2:24:08 PM MC# 2070395: - Stacey L. Gerald, Assistant Administrator/ Chief Safety Officer: From PHMSA reviewed the incident data and other information concerning the safety performance of nurse tanks. We agree that additional requirements, including periodic testing, should be considered. PHMSA is currently considering alternatives for specific measures to improve the safety of nurse tanks, including the costs and benefits of such measures. Industry has inspected more than 1,000 tanks for inclusion in the inspection and testing program authorized by a special permit. We met with the Fertilizer Institute on June 6 to discuss the safety problems identified by NTSB and alternatives for addressing those problems. We discussed the industry’s experience with the inspection program required by the special permit and development of an industry standard for maintaining nurse tanks, including periodic testing and inspections. We plan additional meetings with stakeholders as we continue to evaluate alternatives for enhancing nurse tank safety.

From: PHMSA
To: NTSB
Date: 4/14/2006
Response: In its 4/14/2006 report to Congress, "National Transportation Safety Board (NTSB) and DOT Office of Inspector General (OIG): Open Safety Recommendations on Pipeline and Hazardous Materials Safety," the DOT wrote:In a letter to NTSB issued September 28,2004, PHMSA agreed to evaluate the extent and sever& of the safety problems involving nurse tanks by examining incident data and evaluating alternatives, including periodic inspections and testing, to address the safety problems identified. PHMSA requested classification as "Open, Acceptable Alternative Action." After review of incident data and other information concerning the safety perfmance of nurse tanks, we agree with NTSB that additional requirements, including periodic testing, should be considered. PHMSA is currently considering alternatives for specific measures to improve the safety of nurse tanks with a view towards proposing such measures in an upcoming rulemaking.

From: NTSB
To: PHMSA
Date: 3/7/2005
Response: The Safety Board notes RSPA's agreement with the Board that, because periodic inspection and testing of nurse tanks are not currently required, defects could result in tank leaks, and ruptures may not be detected. However, RSPA further indicates that before it initiates any action (including regulatory action), it will examine the Hazardous Materials Information System and other data to develop information on incidents involving nurse tanks. As we noted in our report of this accident, existing databases do not yield compelling or even accurate information about the extent of nurse tank failures. Nurse tanks are used in farm environments, and accidents may have taken place when the tanks were not in transportation (that is, being transported over public roads). Such accidents might not have been reported to RSPA. The Calamus accident, for example, which took place at a filling station, did not appear in RSPA's accident database. Consequently, while we encourage RSPA to review existing data and perhaps consider collecting more accurate data, implementation of this recommendation can not be contingent on the results of RSPA's review. We specifically stated that although failures of nurse tanks may be rare, when they do occur (as in the case of the Calamus accident), they can be catastrophic, given the extremely hazardous nature of the anhydrous ammonia they contain. For that reason, we believe that periodic nondestructive testing should be conducted regardless of the results of RSPA's review of data. RSPA further indicates that because the welding problem may be more likely to occur in nurse tanks manufactured prior to 1985, RSPA will also ascertain how many of these nurse tanks are still in service, assess the safety issues, and then consider a range of alternatives, including periodic inspections or testing, to address the problem and the costs and benefits of those alternatives. Because RSPA has initiated action on this issue, Safety Recommendation H-04-23 is classified OPEN -- ACCEPTABLE RESPONSE. The Safety Board would appreciate receiving a projected timeframe for fully implementing this recommendation.

From: PHMSA
To: NTSB
Date: 9/28/2004
Response: Letter Mail Controlled 10/5/2004 8:51:30 AM MC# 2040605 - From Samuel G. Bonasso, Deputy Administrator: As your letter notes, under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180), non-specification cargo tanks, including nurse tanks, must be manufactured in accordance with the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code and marked accordingly In addition, a nurse tank must: (1) have a minimum design pressure of 250 psig; (2) be equipped with safety relief valves that conform to requirements in the Compressed Gas Association's Pamphlet S1.2; (3) have a capacity of 3,000 gallons or less; (4) be loaded to a filling density no greater than 56 percent; and (5) be securely mounted on a farm wagon (see 171.315(m) of the HMR). We agree that because periodic inspection and testing of nurse tanks is not currently required under the HMR, defects that could result in tank leaks or ruptures may not be detected. However, before we determine an appropriate course of action, we need to evaluate the extent aid severity of any potential safety problems. To this end, we intend to examine the Hazardous Materials Information System and other data to develop information on incidents involving nurse tanks. In addition, since it appears that the welding problem of concern to NTSB is more likely to occur in nurse tanks manufactured prior to 1985, we need to ascertain how many of these nurse tanks are still in service. Once we have assessed the safety issue to be addressed, we will then consider a range of alternatives, including periodic inspections or testing, to address the problem and the costs and benefits of those alternatives. We request that you classify recommendation H-04-23 as "Open-Acceptable Alternative Action." We thank you for consideration of our request. If you have any questions, please contact me, or James Wiggins, Director, Office of Policy and Program Support, at (202) 366-4831.

From: PHMSA
To: NTSB
Date: 2/28/2004
Response: In its 2/28/2005 report to Congress, "Open Statutory Mandates Regarding Pipeline and Hazardous Materials Safety," the DOT wrote: RSPA is evaluating periodic testing, as well as other alternatives.