IMC-Agrico Company, Port Sutton Terminal - Executive Summary |
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EXECUTIVE SUMMARY - IMC-Agrico, Port Sutton Terminal 1. Accident Release Prevention and Emergency Response Policies The IMC-Agrico, Port Sutton Terminal has a long standing commitment to worker and public safety. This commitment is demonstrated by resources invested in accident prevention, such as personnel training, emergency equipment, participation in emergency drills, and meetings with local emergency response organizations. This commitment is also consistent with the corporation's environmental, health and safety policy which provides that: 1) All facilities will be designed, operated, and managed to protect the health and safety of the employees and the public; 2) All employees will be educated on the applicable environmental, health and safety standards, and procedures; 3) Sufficient human and financial resources will be allocated to sustain these goals; 4) Audits will be conducted regularly to verify compliance with this policy. These corporate policies also empha size the importance of complying with OSHA's Process Safety Management standard, so that all employees and the surrounding community will be adequately protected from potential fire, explosion and /or toxic release hazards associated with catastrophic releases. It is IMC-Agrico's policy to implement reasonable controls to prevent foreseeable releases of regulated and hazardous substances. If an accidental release does occur, IMC-Agrico trained personnel will respond to control and contain the release. IMC-Agrico has a comprehensive program for complying with safety and environmental regulations for all regulated and other hazardous substances handled. 2. Stationary Source(s) and Regulated Substance(s) Handled The IMC-Agrico, Port Sutton Terminal is engaged in the storage and transport of liquefied anhydrous ammonia. Anhydrous ammonia is unloaded from ocean going vessels at the dock and transferred via an aboveground pipeline to an aboveground refrigerated storage vessel. The liquid ammonia, stored in the vessel at approximately -27 degrees F, is subsequently transferred via piping through heat exchangers to a commercial underground pipeline for transport to various end users. Anhydrous ammonia is used to produce various crop nutrients. A small amount of anhydrous ammonia is loaded into cargo tank trucks for shipment offsite to various end users. Anhydrous ammonia is the only regulated toxic substance present at the Port Sutton Terminal that exceeds the threshold planning quantity of 10,000 pounds. 3. Worst-Case Release Scenario(s) and Alternative Release Scenario(s) The worst case release scenario at the Port Sutton Terminal is the loss of the entire contents of the refrigerated anhydrous ammonia storage vessel over a period of ten minutes into a secondary containment structure. The 188 foot diameter retaining wall surrounding the refrigerated anhydrous ammonia storage tank qualifies as passive mitigation and is designed to function without human, mechanica l, or other energy. The retaining wall is designed to hold 110% of the total storage vessel's contents. The release rate is estimated based on the evaporation rate of a liquid pool of anhydrous ammonia with a surface area equal to that within the containment area. Computer modeling was used to predict the distance to the toxic endpoint of 0.14 mg/L and was determined to have off-site impacts. A computer dispersion model, DEGADIS, was selected for the worst case scenario because of its ability to calculate dense gas concentrations and predict plume dispersion behavior. However, this worst case release scenario is unlikely to occur based on the design of the storage vessel and the placement of the vessel within the containment structure. A number of alternative release scenarios were evaluated at the Port Sutton Terminal. Some of these scenarios did not result in offsite impacts. The alternative release scenario resulting in the farthest distance to the toxic endpoint involved failure o f the ten inch diameter ammonia unloading line at the dock area resulting in a release of liquid ammonia over a two minute period. The duration of the release represents the time estimated to shut down unloading operations at typical unloading rates. The release is not contained within a passive mitigation system and thus forms a liquid pool of anhydrous ammonia on the ground which evaporates under weather conditions representative of the nearest average Tampa area meteorological station. Active mitigation measures were not factored into this alternative release scenario. Computer dispersion modeling, again using DEGADIS, predicted the distance to the 0.14 mg/L toxic endpoint to have offsite impacts. However, numerous active mitigation measures are in-place and would be used in the event of an accidental release to reduce the off-site impact thus making the alternative case scenario very conservative. 4. General Accidental Release Prevention Program and Chemical Specific Prevention S teps Anhydrous ammonia is regulated as a highly hazardous chemical under OSHA's Process Safety Management (PSM) standard. Based on the quantity of anhydrous ammonia present at the Port Sutton Terminal, the Port Sutton Terminal is subject to OSHA's PSM requirements, and therefore, the Port Sutton Terminal satisfies the eligibility requirements for a Program 3 Prevention Program under EPA's RMP. The Port Sutton Terminal has fully implemented OSHA's PSM standard requirements and is using this program as its RMP Prevention Program. A brief summary of the facility's PSM program is as follows: The PSM program at the Port Sutton Terminal is an active on-going process with full participation from employees at all levels and from all areas of the facility. The Process Hazard Analysis (PHA) for the anhydrous ammonia system was completed in 1994. All action items generated as a result of the revalidation are being actively pursued for prompt completion. The ammonia storage system was upgraded t o meet applicable nationally recognized codes and standards. The Port Sutton Process Safety Review Committee meets once a month to ensure the implementation and continuation of the entire PSM program. This includes writing and updating operating and maintenance procedures; training for all operators and maintenance personnel; reviewing mechanical integrity, quality assurance, and management of change programs; contractor safety programs; plus developing an audit schedule which meet all OSHA PSM standard requirements. Moreover, the Port Sutton Terminal has numerous active mitigation measures in-place to prevent and/or minimize accidental releases. These measures are commonly referred to as "layers of protection" and they include: vessel construction standards, multiple compressors, a vessel flare, safety relief valves, continuous leak monitoring, manual shutdown procedures, water cannons and extensive operator and maintenance training. In addition, nondestructive testing, for detect ing potential cracks and other forms of corrosion, is conducted on a regular schedule on the storage vessel and associated piping. 5. Five -Year Accident History The five-year accident history includes a review of all accidental releases of regulated substances held above threshold quantities in covered processes that resulted in on-site deaths, injuries, or significant property damage, or known off-site deaths, injuries, evacuations, sheltering-in-place, property damage, or environmental damage. Since June 21, 1994, the Port Sutton Terminal has had no accidental releases which meet the above criteria. 6. Emergency Response Program The Port Sutton Terminal has an emergency response program in place to address foreseeable emergency situations and incidents involving all hazardous substances. The Emergency Response Plan establishes a mechanism for providing hazard and emergency preparedness information to employees, external emergency response agencies, and the community. The Port Sutton Terminal Emergency Response Program contains procedures for notifying plant personnel, the public, and local emergency response agencies about an accidental release. It has been designed to advise all plant personnel how to respond to emergency situations and what their responsibilities are during these emergencies. The Port Sutton Terminal has defined an emergency as a non-routine, unusual set of circumstances that call for immediate safety or environmental action. The Port Sutton Terminal also has an Emergency Action Team on each shift that conducts training and practice drills with county emergency personnel. This team is provided with appropriate personal and mitigation equipment to handle plant emergencies. 7. Planned Changes to Improve Safety The Port Sutton Terminal is working to timely resolve all action items generated as a result of internal audits and process hazard analysis. Although all previous incidents have been thoroughly investigated, the Port Sutton Termi nal is also evaluating the use of root cause investigation and analysis techniques |