Unocal - Swanson River Field Plant # 10 - Executive Summary

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ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES AT SWANSON RIVER FIELD PLANT #10 PROPANE STORAGE TANKS 
 
Safe operations is the number one priority of Unocal Alaska Resources.   
 
As is stated in the Unocal Alaska Resources Health, Environment & Safety Policy, "The Unocal Alaska Resources Oil and Gas Organization is fully committed to a program of responsible management in all areas including health, environment, and safety.  In fulfilling this commitment, we will provide the resources and training to maintain a safe and healthy work area as indicated by Company standards, accepted business practices and compliance with legislative and regulatory requirements.  We will operate our facilities and handle our products in a safe manner to prevent personal injuries/illness and damage to Company property, the environment and the communities in which we operate.  We pledge to work to preserve the quality of our environment through a commitment to reducing or eliminating waste, rec 
ycling, properly disposing of wastes, and reducing emissions. 
 
All employees and contractors are essential to this team effort and must be committed to conducting themselves in a safe and responsible manner, on and off the job.  Every employee and contractor has the responsibility to comply with environmental laws and follow established safety rules, as well as to enforce accident prevention procedures within their operating functions.  Every employee is responsible to promptly report any accident or environmental release to his/her supervisor and also to report and correct, if feasible, any hazardous condition that threatens workplace safety or the environment.  The implementation, maintenance and success of this program will be considered in the measurement of performance." 
 
FACILITY DESCRIPTION OF SWANSON RIVER FIELD PLANT # 10 PROPANE STORAGE TANKS 
 
Swanson River Field Plant # 10 has a small distillation tower that separates liquid propane gas from natural gas liquids.  The liquid  
propane gas is pumped to a set of three interconnected propane storage tanks.  Each storage tank has a maximum capacity of 30,000 gallons, or 126,000 pounds, of propane.  Operationally the tanks are only ever filled to a maximum of 80% of their full capacity, or 100,800 pounds each.  This level is typically reached in the summertime when sales of the product are decreased.  The maximum volume that could legally be put in the tank is 88% of the maximum capacity, or 110,880 pounds of propane. The propane storage tanks contain an amount of propane that is regulated under the Environmental Protection Agency's (EPA's) Risk Management Plan (RMP) rule. 
 
Propane is a flammable material that is used both commercially and by individuals for a variety of uses including home heating, cooking, barbecuing, air conditioning, and to power various devices in recreational vehicles.  The propane from the Swanson River Field Plant # 10 propane storage tanks is sold to a propane distributor who uses a flee 
t of trucks to distribute the propane locally in Alaska.  This reduces Alaskan reliance on propane imported from Canada. 
 
The Swanson River Plant # 10 propane storage tanks are associated with the Swanson River Oil Field, a primary crude oil and natural gas extraction operation which produces naturally occurring hydrocarbons from a structure underneath the Kenai National Wildlife Refuge.  Oil production has occurred in this field since the 1960s.  Road access to the Swanson River Field is restricted by a gated entry, so vehicle traffic to the field is restricted.  The propane storage tanks are located approximately < mile from the Swanson River, which is used for recreational canoeing and fishing. 
 
WORST-CASE RELEASE SCENARIO AND THE ALTERNATIVE RELEASE SCENARIO 
 
The worst-case release scenario is the catastrophic failure and immediate release of the entire contents of a propane storage tank, resulting in a vapor cloud explosion.  Written operating procedures and twice daily visual mon 
itoring prevent more than 24,000 gallons from being present in the 30,000 gallon tank, which is 80% of the actual tank capacity.  Only 800 gallons per day of propane is produced, which is emptied into the propane storage tanks in two batches per day of 400 gallons each.  The operator visually verifies that the level in the storage tanks is such that they will not be overfilled prior to beginning to pump the newly produced 400 gallons of propane into the storage tanks.  
 
The EPA's RMP Guidance for Propane Storage Facilities Reference Tables or Equations were used on an instantaneous release of 110,880 pounds of propane.  This worst-case scenario resulted in a 0.4 mile distance to an endpoint of 1 psi overpressure.  No residences are inside that area, but the area does include the Swanson River Canoe Trail that is used for recreation and impacts the Kenai National Wildlife Refuge since the entire facility is inside the Refuge. 
 
The alternate release scenario is a leak resultant from the  
candelabra style four inch line to the multiple pressure relief valves being sheared off.  The EPA's OCA Guidance Reference Tables or Equations were used on the alternate release of 17,620 lbs of propane.  This alternate scenario resulted in a 0.14 mile distance to an endpoint of 1 psi overpressure.  This release scenario impacts the Kenai National Wildlife Refuge but does not reach the Swanson River. 
 
GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM AND CHEMICAL-SPECIFIC PREVENTION 
 
The Swanson River Field Plant #10 is in compliance with the OSHA Process Safety Management (PSM) prevention requirements.  Hazard analyses of each system are conducted using Hazop techniques.  Prevention process improvements are implemented based on the Hazops.   
 
The Swanson River Field is covered by the Oil Pollution Act of 1990.  An Oil Discharge and Contingency Plan delineates the prevention and response strategies in place at the field. 
 
The Swanson River Field is also in compliance with a federal Spill  
Prevention, Control, and Countermeasure Plan. 
 
Operators take and record visual tank levels every twelve hours to prevent overfilling of the tank.   Daily propane production of 800 gallons is only 1.1 % of the operational 72,000 gallons storage capacity in the interconnected tanks, so it is easy to prevent overfilling.  The propane production process is shut down if the tanks are filled to 80% of their maximum capacity.  
 
FIVE-YEAR ACCIDENT HISTORY 
 
There have been no reportable accidents involving the propane storage system during the last five years. 
 
EMERGENCY RESPONSE PROGRAM 
 
The Unocal Alaska Resources Swanson River Field Emergency Response Plan written document is in compliance with both PSM and RMP requirements.   
 
Emergency response at the Swanson River Field is coordinated with the Kenai Peninsula Borough Central Emergency Services.   
 
Personnel at the field have Hazwoper training to the Hazmat Technician level, and  Fire Training and Emergency Response Refresher Training is  
conducted each year.   
 
Public notification of emergencies is carried out through the Kenai Peninsula Borough 911 system which includes an automatic notification telephone ring down system to alert Borough residents to emergencies which affect them.  There are no residences or public buildings that would be affected by the worst-case scenario. 
 
Public meetings are planned for the Fall of 1999 to inform the public about this Risk Management Plan. 
 
PLANNED CHANGES TO IMPROVE SAFETY 
 
All safety changes to Plant # 10 identified by the PSM Hazop program have been completed.
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