IMC-Agrico Company New Wales Plant - Executive Summary |
|
EXECUTIVE SUMMARY - IMC-Agrico, New Wales Plant 1. Accident Release Prevention and Emergency Response Policies The IMC-Agrico, New Wales Plant 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 emphasize th e 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-Agricos 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, New Wales Plant produces monoammonium phosphate (MAP), diammonium phosphate (DAP), and granular triple superphosphate (GTSP) crop nutrients, as well as a variety of animal feed ingredients. The raw materials used in this process include molten sulfur, phosphate rock and anhydrous ammonia. The sulfur is burned with air in an enclosed vessel to produce sulfur dioxide. The sulfur dioxide is then converted to sulfur trioxide and mixed with water to produce sulfuric acid. In turn, the sulfuric acid is reacted with phosphate rock to produce phosphoric acid. Phosphoric acid is then reacted with the anhydrous ammonia to produce the mono- and diammonium phosphates. Regulated toxic substances involved in this process include: anhydrous ammonia, sulfur dioxide and sulfur trioxide. However, anhydrous ammonia is the only regulated toxic substance that exceeds the threshold planning quantity (i.e., 10,000 pounds) in the process. As sulfur dioxide and sulfur trioxide are fully consumed as intermediates in the production process, they are not present in quantities in the process that exceed their applicable threshold planning quantities. Anhydrous ammonia is stored in four aboveground interconnected horizontal cylindrical pressurized storage vessels at the New Wales plant. The anhydrous ammonia is received at the New Wales plant via a commercial pipeline. 3. Worst-Case Release Scenario(s) and Alternative Release Scenario(s) The worst case release scenario at the New Wales Plant is the loss of the entire contents as a gas of a single anhydrous ammonia storage vessel over a period of ten minutes. No liquid pooling was considered to occur during the release of the anhydrous ammonia which is liquefied in the storage vessel by pressure. Administrative controls limit the storage of anhydrous ammonia in the vessel to 85% of the vessels capacity. 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 material properti es of the liquefied anhydrous ammonia and the design of the pressurized storage vessel. A number of alternative release scenarios were evaluated at the New Wales Plant. Most of these scenarios did not result in offsite impacts. The alternative release scenario resulting in the farthest distance to the toxic endpoint involved the release of the entire contents of one pressurized anhydrous ammonia storage vessel due to a tank rupture. All of the anhydrous ammonia vapor and half of the liquefied anhydrous ammonia when released from the vessel forms a two-phase (i.e., vapor with entrained liquid droplets) hemispherical cloud which begins dispersing downwind immediately. The release duration was calculated to be forty-seven minutes. The remaining liquid anhydrous ammonia forms a pool on the ground at the base of the vessel which then evaporates under weather conditions representative of the nearest average Tampa area meteorological station. Administrative controls limit the quantity of th e stored anhydrous ammonia to 85% of the vessel's capacity. Check valves and excess flow valves were considered active mitigation in determining the quantity of anhydrous ammonia released in this scenario. Computer dispersion modeling, again using DEGADIS, predicted the distance to the 0.14 mg/L toxic endpoint to have offsite impacts. 4. General Accidental Release Prevention Program and Chemical Specific Prevention Steps 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 New Wales plant, the New Wales plant is subject to OSHAs PSM requirements, and therefore, New Wales plant satisfies the eligibility requirements for a Program 3 Prevention Program under EPAs RMP. The New Wales Plant has fully implemented OSHAs PSM standard requirements and is using this program as its RMP Prevention Program. A brief summary of the facilitys PSM program is as follows: The PSM program at the New Wales plant 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 and a revalidation was completed in 1998. All action items generated as a result of the revalidation are being actively pursued for prompt completion. The ammonia storage system was upgraded to meet applicable nationally recognized codes and standards. The ammonia feed system to the granulation plants was carefully analyzed and all action items were resolved. The New Wales 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 developi ng an audit schedule which meet all OSHA PSM standard requirements. 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 New Wales Plant has had no accidental releases which meet the above criteria. 6. Emergency Response Program The New Wales Plant 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 New Wales Emergency Response Program contains procedures for notifying plan t 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 New Wales Plant has defined an emergency as a non-routine, unusual set of circumstances that call for immediate safety or environmental action. The New Wales Plant 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 New Wales Plant 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 New Wales Plant is also evaluating the use of root cause investigation and analysis techniques to enhance the plan ts ability to prevent recurrence of incidents. |