J.R. Simplot Aberdeen Processing Plant - Executive Summary |
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Executive Summary J.R. Simplot's Aberdeen Processing Plant has a large refrigeration system to quickly freeze and store the potato products that it produces. The system has a computerized process control system that monitors system performance and controls its operation. Ammonia is used as a refrigerant in this system. Due to the size of the processing and storage areas, approximately 42,000 pounds of ammonia are contained in the refrigeration system. Ammonia is a colorless gas with a pungent order that is an irritant to the eyes, nose and throat. It is normally shipped as a liquified compressed gas and is present in portions of the refrigeration system as a liquid under pressure. In order to protect its employees, the public, and the environment, the Aberdeen Processing Plant has an integrated safety management program to prevent ammonia releases and mitigate the consequences of a release, should one occur. The Plant Engineer is responsible for overall management of this progra m. It is designed to comply with OSHA's Process Safety Management Standard (PSM) found in Title 29 of the Code of Federal (CFR) Regulations 1910.119 and EPA's Risk Management Program Regulations found at 40 CFR Part 68. In the worst case release scenario defined by EPA, the largest vessel of ammonia is released over ten minutes under very calm atmospheric conditions. Under these conditions, hazardous concentrations of ammonia could extend 1.60 miles from the plant and would required people in the affected area to go indoors and remain until the release dissipated. This could include the entire town of Aberdeen depending on the atmospheric conditions and wind direction. A more credible release scenario involves up to a quarter inch diameter leak in a transfer line or in valve packings. This could result in hazardous concentrations of ammonia to a distance of 0.19 miles from the plant. Under the right wind conditions, hazardous concentrations of ammonia could reach adjacent area s of the golf course, but would not be expected to reach any residences. However, the smell of ammonia at lower concentrations could be detected at nearby residences until the ammonia dissipated. The Simplot Aberdeen plant has an emergency plan that addresses the response necessary for a release of ammonia from the refrigeration system. Because of the pungent odor of ammonia, any leak is easily detected. The compressor rooms are provided with ammonia detectors that sound an alarm if ammonia is detected. The plant maintains a group of maintenance personnel who are trained and qualified to respond to leaks of ammonia. The refrigeration system is designed so that major components can be isolated by closing selected valves. In case of a release that could travel off the plant property, calls would be made to the Aberdeen police and fire departments, and the Bingham County Disaster Services Coordinator to assist in the response. Other state and Federal notifications would be made as required. The Aberdeen plant has experienced only infrequent minor releases that have never been detected beyond the plant boundaries. During the last five years, there has been only one release of ammonia. That release involved a total of approximately five pounds of ammonia. As a result of a recent periodic process hazards analysis of the refrigeration system, two actions are being taken to improve response to an ammonia release. The ammonia sensors in the compressor rooms are being placed on a regular calibration schedule. Wind socks are being installed at various locations so that they can be seen from any outdoor location at the plant. If a release occurs, this will enable employees to quickly determine the direction of a release and to stay upwind. It will also provide a quick indication of whether the release is traveling toward the populated area in Aberdeen. |