AMI Doduco, Inc., Plant #1 - Executive Summary

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(a). AMI Doduco's accidential release prevention policy involves a unified approach that integrates technologies, procedures, and managment practices. All applicable proceudres of the US Environmental Protection Agency (EPA) Prevention Program are adhered to.  AMI Doduco's emergency 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 requirments. 
(b).  The AMI Doduco - Plant #1 manufacturing facility located at 1001 E. Smithfield Street, McKeesport, PA has an installed 10,000 gallon above-ground storage tank used to store approximately 35,000 pounds of liquified anahydrous ammonia.  The tank is located on thewest side of the facility.  Liquified ammonia is vaporized prior to entering one of two high temperature dissociator units.  As the ammonia vapors pass through an electrically heated retort, heated to 1750 F, and over a nickel cat 
alyst, 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 liquified ammonia in 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 ther 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 Planning 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 irreverisble 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 potenitally affected."   
 
The worst-case release scenario at the AMI Doduco facility involves a failure of the 10,000-gallon aboveground-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 (between 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 10,500. 
 
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: 
           7 High level of training of the operators. 
           7 
Preventive maintenance program. 
           7 Use of accurate and effective operating procedures, written with the operators. 
           7 Performance of a hazard review of equipment and procedures.  
           7 Implementation of an auditing and inspection program. 
 
(e). There has been one accidential release of ammonia at the facility within the last 5 years.  The accident occurred on April 16, 1996 and resulted in the release of 19.7 pounds of ammonia.  The incident occurred after a LaRoche Industries ammonia delievery vehicle was spotted and the driver removed the unloading hose from the hose trough and removed the hose endcap.  After discovering his vehicle was too far from the loading connenctions on the ammonia storage tank,  the driver attempted to replace the hose back in the hose trough without first replacing the hose endcap.  The driver either accidently turned the handwheel or hit the truck with the hose end valve causing the hose end vaalve to open.  Approximely 20 pou 
nds of liquid anhydrous ammonia was discharged under pressure. Additional details on this incident can be found in AMI's Incident Report File # 041696. 
 
(f). The facility has an emergency response program which has been coordinated and reviewed by Allegheny 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 when an OSHA ProcessSafety Program was completed for the facility.
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