Vermillion Gas Plant - Executive Summary

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   Questar Gas Management Company Risk Management Plan 
   Executive Summary 
 
   Vermillion Gas Plant 
 
 
Accidental Release Prevention and Response Policies 
 
Questar Gas Management Company has a long standing commitment to worker and public safety.  This commitment is demonstrated by the resources invested in accident prevention, such as training personnel and considering safety in the design, installation, operation, and maintenance of our processing plants.   
 
Our policy is to implement reasonable controls to prevent foreseeable releases of regulated substances.  However, if a release does occur, plant personnel will respond to contain and control the release. 
 
 
Description of the Stationary Source and Regulated Substances 
 
The Vermillion Gas Plant is located approximately 55 miles southeast of the town of Rock Springs, Wyoming.     
 
The plant operates a low temperature, liquid separation process for the production of [email protected] natural gas liquids (NGLs).  These liquids are made-up of propan 
es, butanes, and heavier hydrocarbons.   
 
Additionally, dehydrated natural gas (methane, ethane) is produced at the facility.  All of these substances are regulated substances for purposes of risk management planing. 
 
 
Offsite Consequence Analysis Results 
 
The worst-case scenario (WCS) associated with regulated substances in Program Level 1 processes at the plant is a catastrophic failure of a 30,000 gallon Y-grade NGL storage tank.  This results in a release of the entire contents of the largest tank (134,730 pounds of Y-grade NGLs) over a ten minute period.  The resulting vapor-cloud explosion generates a 1 psig over-pressure endpoint approximately 0.4 miles from the center of the plant.  There are no public receptors, environmental receptors, or population centers within the over-pressure area.   
 
Although QGMC has numerous controls in place to prevent such a release and to manage their consequences, no credit for administrative controls or passive mitigation measures were taken int 
o account in evaluating this scenario.    
 
Since this facility qualifies as Program Level 1, no Alternative Release Scenario (ARS) is required.  
 
 
Five Year Accident History 
 
The Vermillion Gas Plant has an excellent record of accident prevention over the past five (5) years.  There have been no onsite or offsite accidents, as defined by EPA=s General Guidance on Risk Management Programs.  
 
 
Emergency Response Program Information 
 
The Vermillion Gas Plant maintains a written Emergency Response Plan, which is in place to protect worker and public safety as well as the environment.  The program consists of procedures for responding to a release of a regulated substance, including the possibility of a fire or explosion if a flammable substance is accidently released.  The procedures address the aspects of emergency response including first aid, evacuation plans and accounting for personnel after an evacuation, notification of local emergency response agencies and the public if a release  
occurs, and the post-incident cleanup requirements.   
 
In addition, the plant has procedures that address maintenance, inspection, and testing of emergency response equipment as well as instructions that address the use of emergency response equipment.   
 
Employees receive training in these procedures as necessary.   
 
The Emergency Response Plan is updated as needed.
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