General Motors Bowling Green Assembly Plant - Executive Summary

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General Motors Corporation (GMC) is required to develop a management system for the plant to oversee the implementation of the accidental release prevention program.  GMC has assigned the Environmental, Health, and Safety(EHS) leader the responsibility for the development, implemetation, and integration of the risk management program elements.  In the case of an accidental release, the coordinator is responsible for evaluating the severity of the accident.  Based on this evaluation, the coordinator is responsible for contacting the local, state, and federal response centers for the appropriate level of assistance and information. 
To continue operating under safe conditions, GMC will maintain certain ranges of upper and lower temperatures, flows, and compositions. 
The General Motors Bowling Green Assembly Plant has an area of about one million square feet and is a manufacturer of the Corvette, a luxury sports car.  Propane is the only regulated substance used at this facility that req 
uires a risk management plan to be in effect.  The sole use for the propane is to be used as back up fuel, should the natural gas supply be suddenly terminated.  The propane is stored in a fenced Propane Tank Farm on site in one 27,000 gallon and nine 30,000 gallon tanks.  This amounts to a maximum storage of 1,002,577 pounds. 
The United States Environmental Protection Agency Offsite Consequences Analysis (U.S. EPA OCA) guidance document provided a screening level method for this plant that involved look-up tables assessing the potential offsite impacts.  In the risk management plan a worst case scenario and two alternative release scenarios have been calculated.  All scenarios assume a vapor cloud explosion and an overpressure of 1 psi as the endpoint. 
The worst case scenario involves the largest quantity of a regulated substance from a single vessel that results in the greatest distance to an endpoint.  The scenario assumes that only one 30,000 gallon tank is effected.  The maximum 
amount of propane that tank stores is 101,640 pounds.  The greatest distance to endpoint for the largest tank is 0.377 of a mile.  Business, including the Corvette Assembly Plant, special facilities, and residences are located within this radius. 
The first alternative release scenario is a valve failure.  The longest period of time for which a stream of propane escaping from one of the pipes may not be noticed is 60 minutes.  This would result in 7080 pounds of propane released, which would cause the explosion to effect everything within 0.155 miles of the source.  This impacts residences on Harrison Road. 
The second alternative release scenario assumes a hose rupture caused by an accidental pull-away of an unloading truck and includes the use of an active mitigation system.  This assumes that the shut off valves (active mitigation devices) operate as designed.  The hose for the calculation is 4 inches in diameter and 25 feet long and would release 68.59 pounds of propane.  The grea 
test distance to endpoint for this pull-away explosion is 0.033 miles or 174.8 feet.  There would be no offsite consequences. 
The accidental release prevention program at the Bowling Green facility complies with 40 CFR Part 68, for the Program 2 Prevention Program.  This facility also complies with NFPA 58, 1998 Edition. 
A hazard review will be updated at least once every five years.  If there are any major changes within the propane storage operation, a hazard review will be performed before startup of the changed process.  All of the pumps, compressors, valves, gauges, temperature indicators, pressure relief devices, vaporizers, and piping are in conformance with the Fire Marshall's approval based on the engineering and design plans submitted for the permit indicating that all of the equipment meets the requirements of NFPA 58. 
GMC is required to certify that this facility has evaluated compliance at least every three years to verify that the procedures and practices under the rul 
e are adequate and are being followed. 
GMC has no record or knowledge of any propane-related instances in the past five years that may have caused on-site deaths, injuries, or significant property damage at the Bowling Green Assembly Plant.
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