AMI Doduco, Inc., Plant #3 - Executive Summary |
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(a). AMI Doduco's accidental release prevention policy involves a unified approach that integrates technologies, procedures, and management practices. All applicable procedures of the US Environmental Protection Agency (EPA) Prevention Program are adhered to. AMI Doduco's emergency response policy involves the preparation of response plans which are tailored to each facility and to the emergency response services available in the community, and is in compliance with the EPA emergency response requirements. (b). The AMI Doduco - Plant #3 manufacturing facility located at 1820 Colonial Village Lane, Lancaster, PA has an installed 10,000 gallon above-ground storage tank used to store approximately 35,000 pounds of liquefied anhydrous ammonia. The tank is located on the west side of the facility. Liquefied ammonia is vaporized prior to entering one of three high temperature dissciator units. As the ammonia vapors pass through an electrically heated retort, heated to 1750 F, and over a nickel catalyst, the ammonia is "cracked" into a mixture of 75% hydrogen and 25% nitrogen. The "cracked" ammonia is dried before entering individual electric furnaces where it creates a reducing internal furnace atmosphere. (c). The offsite consequence analysis includes consideration of the release of 35,000 pounds of liquefied ammonia in a 10 minutes as a "worst case release" and the release of 500 pounds in 60 minutes as an "alternative scenario". The first scenario is defined by EPA, which states that "the owner or operator shall assume that the ... maximum quantity in the ... is released as a gas over 10 minutes", due to an unspecified failure. The alternative scenario is defined as "more likely to occur than the worst-case release scenario." Atmospheric dispersion modeling is performed to determine the distance traveled by the ammonia released before its concentration decreases to the "toxic endpoint" selected by EPA of 0.14 mg/l, which is the Emergency Response Planni ng Guideline Level-2 (ERPG-2). This is defined as the "maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms which could impair an individuals ability to take protective actions". The residential population within a circle with a radius corresponding to the toxic endpoint distance is defined , " to estimate the population potentially affected." The worst-case release scenario at the AMI Doduco facility involves a failure of the 10,000 gallon above-ground liquefied anhydrous ammonia tank. The offsite consequence analysis for this scenario was performed using EPA's pre-defined conditions. That is, the release of the entire amount of ammonia, (35,000 pounds), in 10 minutes and using the one-hour average ERPG-2 as the toxic endpoint distance. These conditions however may be unrealistic because: 1. Only a fraction (betw een 20 - 50 % of the total) of the liquefied ammonia released flashes as a vapor. The remaining unflashed liquid form a liquid pool, spreading on the surface of a water body or on the ground. Initially, vapors are rapidly released in the form of a "puff". The evaporation process cools the spilled liquid and underlying ground, slowing the vapor release rate after the initial puff. It may also adsorb onto the soil at a rate dependent on the soil type and its degree of saturation with water. 2. Only the population within an elliptical plume extending downward of the release point is potentially affected. The plum area or footprint, is approximately 25% (one-quarter) of the area of the full circle. EPA mandated meteorological conditions, stability F, wind speed of 1.5 m/sec, highest daily maximum temperature (116 F), and average humidity (65%) were used. Atmospheric dispersion modeling for the worst case scenario performed using the EPA assumptions, a distance to the toxic endpoint is 2.3 miles and an estimate of residential population potentially affected is 12,165. The alternative release scenario involves the failure or rupture of a one (1) inch diameter ammonia vapor feed line to the dissociator. The amount of ammonia released might be 500 pounds, at an average rate over one hour (the duration of the release) of 8.3 pounds per minute. Toxic endpoint distance was obtained, which is defined by ACGIH as "the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to one hour without experiencing or developing life-threatening health effects". The typical meteorological conditions used were stability F, wind speed 2.0 m/sec., average air temperature 75 F, and 63% average humidity. The estimated distance traveled to the toxic endpoint is 0.1 miles. (d) AMI Doduco's general accidental release prevention program is based on the following key elements: - High level of training of the op erators. - Preventive maintenance program. - Use of accurate and effective operating procedures, written with the participation of the operators. - Performance of a hazard review of equipment and procedures. - Implementation of an auditing and inspection program. (e) No accidental release of ammonia has occurred at this facility in the past five years. (f) The facility has an emergency response program which has been coordinated and reviewed by Lancaster County's Emergency Management, which is a member of the Local Emergency Response Planning Committee (LEPC). This program includes an emergency response and notification plan. Emergency response drills and/or evaluations are conducted annually. Emergency operations and response procedures are also reviewed at this time. (g) No changes to improve safety were identified on October 24, 1996, when an OSHA Process Safety Program was completed for the facility. |