Thorn Apple Valley, Ponca City Division - Executive Summary |
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Executive Summary The Accidental Release Prevention and Emergency Response Policies In this facility, the Company uses Anhydrous Ammonia, which is considered hazardous by the Environmental Protection Agency. This chemical is used to provide cooling through the entire plant. It is Company policy to have programs in place dealing with safety precautions in handling this substance and to prevent unnecessary human exposure, to reduce the threat to our own personal health as well as our co-workers, and to reduce the threat to nearby members of the community. It is Company policy to adhere to all applicable Federal and state rules and regulations. Safety depends upon the manner in which ammonia is handled combined with the safety devices inherent in the design of this facility coupled with the safe handling procedures used, and the training of personnel. Our emergency action plan is coordinated with the Kay County LEPC to notify them through the emergency response plan to respond to i ncidents that may affect the public. Sources and Process Description Thorn Apple Valley Ponca City facility is in the business of processing raw pork products into ready to eat sliced meat, and other ham and turkey products. These products require cooling of the materials during and after being processed. Anhydrous Ammonia is the refrigerant used for the cooling process due its low cost in maintaining the medium and the low temperatures necessary in this industry. The ammonia is enclosed within a closed loop system that removes heat from the products and the storage rooms. The ammonia is evaporated form the product and cooling areas by removing heat from the products at low temperatures (-10 F) and pressures (9 psig) and is then compressed to high pressures (181 psig) to be condensed at normal atmospheric temperatures to remove the heat from the system by outside air. The ammonia system at the Thorn Apple Valley contains 38,000 pounds of ammonia. Summary of Major Hazards Con sequence of Failure to Control Hazards Ammonia Health Hazards Ammonia is a colorless gas with extremely pungent odor. Liquid ammonia vaporizes to a poisonous gas cloud. Ammonia is a sever irritant of the eyes. It penetrates the eyes more readily than any other alkali. Contact with liquid anhydrous ammonia and concentrated solutions can produce severe eye injury or blindness. Exposure of the eyes to high gas concentrations can cause temporary blindness and severe eye damage. Laceration or watering of the eyes can occur upon exposure to 150 PPM ammonia gas and higher. Ammonia is an irritant by inhalation. At increasing concentrations it can cause symptoms ranging from runny nose, coughing, chest pain, trouble with breathing, and death. It can cause severe breathing difficulties that are delayed in onset. Inhalation of concentrations of 2500 to 6500 PPM causes shortness of breath, bronchospasm, chest pain, and pulmonary edema (filling of the lungs with fluid) that may be fa tal. Exposure of the skin to liquid anhydrous ammonia or high concentrations of the gas can cause first an second degree burns of the skin. Vapor concentrations of 10,000 PPM are mildly irritating to moist skin, while 30,000 PPM or greater causes a stinging sensation and can produce skin burns and blisters. These high concentrations of ammonia are corrosive to moist skin and other moist body tissues. Physical Hazards Ammonia or ammonia with oil or other debris is an explosion hazard when exposed to flame of fire. The Lower Explosive Limit (LEL) is 16 % and Upper Explosive Limit (UEL) is 25 % by volume in air. Elevated temperatures can cause containers of the substance to explode. Ammonia emits toxic fumes when exposed to heat. When heated to temperatures above 850 degrees F, ammonia will emit hydrogen gas. The auto ignition temperature is 1204 deg. F if catalyzed by iron. Common Exposure Control Methods -Process Enclosure -Local Exhaust Ventilation -General Dilution Venti lation -Personal Protective Equipment -Use of Water -Area Monitoring (with alarm systems) Potential for Exposure to Ammonia The refrigeration operation is a closed system with no purposeful exposure to ammonia. As a closed system, exposure potentials are primarily related to equipment failure, fugitive emissions from improperly adjusted or worn valve packing, pump and compressor seals and pipe connector gaskets, or mistakes in operation of the system. Worst Case Scenario - Toxic Case The work case scenario for toxic substances used at the Thorn Apple Valley site is the release of 24,000 pounds of ammonia from the systems largest vessel (Vessel #1, a High Temperature Recirculator) in a 10 minute period. The toxic endpoint was determined by using the Cameo\Marplot\Aloha computer-modeling program. With a wind speed of 1.5 m/sec and a Stability Class of E in an urban topography the endpoint of the spill was determined to be 1.2 miles from the vessel ( See Attachment 1 for calculati ons). The plant site is located in the industrial park of Ponca City, Oklahoma. The public receptors within a radius of 1.2 miles from the plant site are nursing home, school, residential area, and airport with a populations of approximately 975. A map showing the receptors within the radius of the worst case release is shown in Attachment 1. In case of a major leak, passive mitigations in place are drains that go to a our wastewater pre-treatment facility where we have the ability to contain and treat the spill. Alternate Case Scenario - Toxics Alternate case scenarios for Thorn Apple Valley were reviewed by the maintenance and operating sections. Considerations were given to the most probable cause of a leak within the ammonia system. The possible leak scenarios considered were: -Process piping Failure -Process vessel or pump releases from seals, drains, or bleeds -Rupture of sight glass -Overpressure and release through relief valves After discussing these and the operatio ns of the refrigeration system, it was decided that the failure of a pump seal was the most probable cause of a leak within the system. Calculations (See Attachment 2 for calculations) were make considering the leakage of high-pressure ammonia liquid from the high-pressure receiver. The failure would create a .5 square inch orifice. At the system pressures, it was determined that a release rate of 724 lbs./min would be released for 20 minutes for a total of 14,480 lbs. if this incident occurred. Wind speeds of 3 m/sec and a stability class of D was used. The toxic endpoint was determined to be 568 yards by using the Cameo/Marplot/Aloha computer modeling program. In this alternate case scenario there would be no public population exposure. There were no active or passive mitigation credits for this scenario. The Five Year History Thorn Apple Valley, Ponca City has only been on-line for 3 years. In this three year period we have not had any incidents of any significant quantity . Historically, exposures to ammonia most often occur from: -Ammonia contained in oil removed from compressors in preventative maintenance programs. Management System Thorn Apple Valley has a management system in place to administer the RMP prevention program. The Environmental Safety and Health Manager is the responsible person for leading this program. Thorn Apple Valley is in compliance with OSHAs Process Safety Management rule. The RMPs accidental release preventative program is covered by the elements of the PSM program. Control of these events are acquired by: -An effective preventative maintenance program -Review for proper design -Development of and following operating procedures -A mechanical integrity program -Training to be aware of potential exposure situations and using exposure prevention procedures and/or protective equipment Emergency Response Plan An emergency response plan is in place at Thorn Apple Valley to deal with incidents and emergencies that mi ght take place on site. The site maintains its own HAZMAT Teams. Training for these functions is given annually. Onsite drills are also scheduled as part of the emergency response plant to familiarize employees of the dangers of ammonia and the proper response to alarms and evacuations. Coordination with the LEPC has been to provide notification them through the emergency response plan to respond to incidents that may affect the public. |