Thorn Apple Valley - Executive Summary |
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THE ACCIDENT RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES In this facility, we use Anhydrous Ammonia and propane, which are considered hazardous by the EPA. These chemicals must be used to provide cooling for the process and controlling the humidity in the areas. It is our policy to have programs in place dealing with safety precautions in handling these substances 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 our policy to adhere to all applicable Federal and state rules and regulations. Safety depends upon the manner in which we handle ammonia and propane combined with the safety devices inherent in the design of this facility combined with the safe handling procedures that we use and the training of our personnel. This facilities emergency response program is based on the IIAR's "Risk Management Guidelines Program for Ammonia Refrigera tion" and NPGA's LP Gas Handbook, "Guidelines for Developing Plant Emergency Response Procedures." The plan has been provided and reviewed with the Onslow County Local Emergency Planner Center. Coordination with the LEPC has been made to notify them through the emergency response plan to respond to incidents that may affect the public. STATIONARY SOURCES AND REGULATED SUBSTANCES HANDLED The Thorn Apple Valley's manufacturing facilities is in the business of processing pork bells into bacon. These products require controls for humidity and cooling of the materials during and after being processed. There are two hazardous chemicals (Anhydrous Ammonia and propane) used at this site for these purposes. Anhydrous Ammonia is the refrigerant used for the cooling process due to the low cost of the medium and the low temperatures that must be obtained. The ammonia is enclosed within a closed loop that removes heat from the products and storage rooms. The ammonia is evaporated by remov ing heat from the products and cooling areas at low temperatures and pressures and then dispenses the heat at high pressures and temperatures to outside air. The ammonia system at the Thorn Apple Valley contains 15,000 pounds of ammonia. Propane is also used at the facility. Propane is used in dryers to control the humidity in the processing rooms. It is received from retailers by truck and stored in five 1000 gallon, one 500 gallon and one 250 gallon tanks. The maximum inventory of any of the tanks is controlled at 85 percent level. The maximum amount of propane that can be stored at this plant is 20,821 pounds. SUMMARY OF MAJOR HAZARDS CONSEQUENCE 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 severe 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 fatal. Exposure of the skin to liquid anhydrous ammonia or high concentrations of the gas can cause first and 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 or 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 8500F, ammonia will emit hydrogen gas. The auto ignition temperature is 12040F if catalyzed by iron. Ammonia can react to form potential violent or explosive reactions with halogens (e.g., chlorine, bromine). It can react to form potential violent or explosive reactions with strong oxidizers, hypochlorite bleaches, silver compounds, mercury compounds, gold, other metals, and acids. Common Exposure Control Methods - Process enclosure - Local exhaust ventilation - General dilution ventilation - 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 packings, pump and compressor seals and pipe connector gaskets, or mistakes in operation of the system. Propane Health Hazards Propane is a colorless gas with faint petroleum like odor. It is shipped as a liquefied gas under its vapor pressure. For transportation it may be stenched. Contact with the liquid can cause frostbite. It is easily ignited. Its vapors are heavier than air and a flame can flash back to the source of leak very easily. This leak can be either a liquid or vapor leak. It can asphyxiate by the displacement of air. Under fire conditions the cylinders or tank cars may violently rupture and rocket. WORST CASE SCENARIO - TOXIC CASE The worst case scenario for toxic substances used at the Thorn Apple Valley site is the release of 7,760 pounds of ammonia from the system's largest vessel, the R-2 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 F in an urban topography the endpoint of the spill was determined to be 0.94 miles from the receiver. The plant site is located in the suburb of the city of Holly Ridge, North Carolina. The public receptors within a radius of 0.94 miles from the plant site are schools, residents, and downtown office buildings with a population of 104. In case of a major leak, passive mitigations in place are drains that go to a collection tank for the ammonia area. WORST CASE SCENARIO - FLAMMABLE SUBSTANCE Propane is used at the Thorn Apple Valley site and falls into EPA's Program 2. The worst case scenario for propane was calculated using a 1000-gallon storage tank tha t is one of the largest tanks installed on site. The endpoint was calculated to be .12 miles from a source release of 3,624 pounds. The company policy is to limit filling the storage tanks to 85% capacity. It was assumed that the entire contents of the storage tank were released as a vapor and 10% of the released quantity was assumed to participate in the resulting explosion. The endpoint was determined using the "RMP Offsite Consequence Analysis Guidance" manual and RMP Comp computer program. This endpoint will extend beyond the facility boundary. ALTERNATE CASE SCENARIO - TOXICS Alternate case scenarios for the Thorn Apple Valley was 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: - Transfer hose rupture - Process piping failure - Process vessel or pump releases from seals, drains, bleeds- - Rupture of a sightglass - Overpressure and release through relief valves After discussing these and the operations of the refrigeration system, it was decided that the rupture of a sightglass was the most probable cause of a leak within the system. Calculations were made considering the leakage of high-pressure ammonia liquid from the high-pressure receiver. The breakage would create a 0.5" orifice in the sight glass. At the system pressures, it was determined that a release rate of 391 lbs./min would be released for 7 minutes if this incident occurred. Wind speeds of 3.0 m/sec and a stability class of D were used. The toxic endpoint was determined to be 0.57 miles by using the Cameo/Marplot/Aloha computer-modeling program The public receptors in this area would include residents and public recreational areas. The population of this area would be 21. There were no active or passive mitigation credits for this scenario. ALTERANTE CASE SCENARIO - FLAMMABLE SUBSTANCE An alternate case scenario for pro pane was calculated resulting in a rupture of a one-inch line on a 1000-gallon storage. This resulted in a leak of 2960 pounds of propane in a 10-minute period. The endpoint was calculated to be 0.07 miles from the source of release. The endpoint was determined using the "RMP Offsite Consequence Analysis Guidance" manual and RMP Comp computer program. This endpoint will extend beyond the facility boundary. THE FIVE YEAR HISTORY There have been five incidents during the last five years at the Thorn Apple Valley plant site involving ammonia. Four of these resulted from equipment failures such as seal leaks on pumps and sight glasses and a safety relief valve release. None of these resulted in reportable leaks of over 100 pounds, injuries, deaths or damage to the environment. These incidents were investigated and improvements in maintenance practices and equipment upgrades were made. The fifth incident occurred during a hurricane in 1996. The hurricane broke an ammonia pipel ine and resulted in 952 pounds being released over a fourteen-day period. From this incident, maintenance and operating procedures were modified and the emergency response plan's action plan was revised to deal with hurricanes. The propane system was started up in October 1998 and there have been no releases that have caused offsite impacts as specified in the risk management rule (40 CFR 68.10(b)(1)). How Releases are Prevented Historically, exposures to ammonia most often occur from: - Leaking valve stem packing glands while opening or closing a valve - Leaking at valve flanges or other piping connections - Pressurizing any equipment with sight glasses. especially the round type - Mistakenly venting gas through open equipment to the atmosphere - Malfunctioning pressure relief valves - Mechanical seal failures on compressors and pumps RELEASE PREVENTION PROGRAM AND PREVENTION STEPS Thorn Apple Valley complies with the EPA's Accidental Release Preventative Rule with all applicable state codes and regulations for ammonia and propane. Management systems are in place to administer the RMP prevention programs for ammonia and propane. The Environmental Safety and Health Manager is the responsible person for leading this program. Thorn Apple Valley is in compliance with OSHA's PSM rule for ammonia. The RMP's accidental release preventative program for ammonia is covered by the elements of the PSM program. Controls for the preventative programs are acquired by: - Effective preventative maintenance programs - Reviews for proper design - Development of and following operating procedures - A mechanical integrity program that includes equipment testing procedures - Training to be aware of potential exposure situations and using exposure prevention procedures and/or protective equipment. EMERGENCY RESPONSE PLAN This facilities emergency response program is based on the IIAR's "Risk Management Guidelines Program for Ammonia Refrig eration" and NPGA's LP Gas Handbook, "Guidelines for Developing Plant Emergency Response Procedures." An emergency response plan is in place at Thorn Apple Valley to deal with incidents and emergencies that might take place on site. The site maintains it's own HAZMAT teams. Training for these functions is given annually per state requirements. Onsite drills are also scheduled as part of the emergency response plan to familiarize employees of the dangers of ammonia and propane and the proper response to alarms and evacuations. The plan has been provided and reviewed with the Onslow County Local Emergency Planner Center. Coordination with the LEPC has been made to notify them through the emergency response plan to respond to incidents that may affect the public. PLANNED CHANGES TO IMPROVE SAFETY Thorn Apple Valley is putting together a training program to enhance the skills of the refrigeration operators and to increase their abilities to respond to emergencies. This includes offsite refrigeration training courses, operating procedure reviews and drills. |