Marathon Oil Company - Yates Gas Plant - Executive Summary

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   Risk Management Plan 
   Yates Gas Plant 
   Yates Field Unit 
   Marathon Oil Company 
   Pecos County, Texas 
I.    Accidental Release Prevention and Response Policies 
Marathon Oil Company (Marathon) has a long-standing commitment to worker and public safety, and to the environment.  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 the plant.  Marathon's policy is to implement reasonable measures to prevent foreseeable releases of regulated substances.  However, if a release does occur, trained personnel will respond to effectively control, contain and mitigate the release. 
II.    Description of the Stationary Source and Regulated Substances 
The Yates Gas Plant (YGP) in the Yates Field Unit, located near Iraan, Texas, extracts natural-gas liquids from natural gas and manufactures sweet fuel gas for plant and field consumption.  The plant c 
ontains several regulated flammable substances including methane, ethane, propane, butane, and pentane.  The plant does not have any regulated toxic substances with an amount greater than the threshold quantity specified in 40 CFR 68.  
III.    Offsite Consequence Analysis Results 
The worst case scenario (WCS) associated with a release of flammable substances at the YGP is a vapor cloud explosion (VCE) involving the full inventory of the largest storage tank.  This scenario involves a release of 47,000 lbs of propane.  This inventory is assumed to release and ignite, resulting in a VCE.  The maximum distance to the 1-psi endpoint for this WCS is 0.29 miles.  Although there are numerous controls at the YGP to prevent such releases and to mitigate their consequences, no credit for passive mitigation measures was taken into account in evaluating this WCS. 
IV.    General Accident Release Prevention Program 
The accident prevention program in place at the YGP is summarized in the following.  Be 
cause this facility is also subject to the Occupational Safety and Health Administration's (OSHA's) process safety management (PSM) standard, this summary addresses each of the OSHA PSM elements and describes the management system in place to implement the accident prevention program. 
   A.    Employee Participation 
   Marathon ensures its employees participate in all development, review and implementation aspects of PSM and accident prevention.  Examples of employee participation include compiling and updating technical documents, chemical information and operating procedures; participating in and providing suggestions on the emergency response drills; and participating as a member of a process hazard analysis (PHA) team, an incident investigation team, or an audit team.  Employees have access to all information created as part of the gas plant accident prevention program.  Specific ways that employees can be involved in the accident prevention program are documented in an employee partic 
ipation plan that is maintained at the plant. 
   B.    Process Safety Information 
   Marathon personnel maintain a variety of technical documents that are used to ensure safe operation of the processes.  These documents address hazards of the highly hazardous chemicals at the plant, process technology, and process equipment.  Specific personnel within the gas plant and at the Midland Region office are assigned responsibility for maintaining up-to-date process safety information.  A PSM information reference form is utilized to document the location of this information. 
   Chemical-specific information, including exposure hazards and emergency response/exposure treatment considerations, is provided in material safety data sheets (MSDS).  Documents maintained on file include process flow diagrams, a description of the process, the maximum intended inventory, safety-related limits for process parameters (e.g., temperatures, pressures, flows, compositions), and an evaluation of the consequences  
of deviation from defined safe operating limits.  Trained Marathon operating personnel ensure that the process is maintained within these limits using process controls and monitoring instruments, and protective instrument systems (e.g., automated shutdown systems). 
   Technical documents that provide information about the design and construction of process equipment are also maintained.  This information includes materials of construction, piping and instrumentation diagrams, electrical classification, relief system design and design basis, ventilation system design, design codes and standards, and safety systems (e.g., interlocks, detection and suppression systems).  This information, in combination with written procedures and trained personnel, provides a basis for establishing inspection and maintenance activities.  
   All changes to the process chemicals, technology or equipment are subject to the Management of Change program (Item J below) to ensure that safety features in the proce 
ss are not compromised. 
   C.    Process Hazard Analysis (PHA) 
   Marathon has a comprehensive program to ensure that hazards associated with the processes at the plant are identified and controlled.  Within this program, the process is systematically examined to identify hazards and ensure that adequate controls are in place to manage these hazards. 
   The Hazards and Operability (HAZOP) and "what-if" analysis techniques are primarily used to perform these evaluations.  The analyses are conducted using a team of people who have operating, maintenance, engineering, and safety expertise.  This team identifies and evaluates hazards of the process as well as accident prevention and mitigation measures, and the team makes recommendations for additional prevention and/or mitigation measures when the team believes such measures are necessary. 
   The PHA team findings are forwarded to local management for resolution.  All approved mitigation options in response to PHA team findings are tracked until 
they are completed.  The final resolution of each finding is documented and retained. 
   To ensure that the process controls and/or process hazards do not eventually deviate significantly from the original design safety features, the plant periodically updates and revalidates the hazard analysis results.  These periodic reviews are conducted at least every five years and will be conducted at this frequency until the process is no longer operating.  The results and findings from these updates are documented and retained.  Once again, the team findings are forwarded to local management for consideration, and the final resolution of the findings is documented and retained. 
   D.    Operating Procedures 
   Marathon maintains operating procedures and manuals that address various modes of process operations, such as unit startup, normal operations, normal shutdown, temporary operation, emergency operations, emergency shutdown, and initial startup of a new process.  The procedures and manuals incl 
ude operating limits that outline consequences of process deviation and steps required to correct or avoid deviations.  They also include safety and health considerations, and safety systems and their functions.  These procedures and manuals can be used as a reference by experienced operators and provide a basis for consistent training of new operators.  The procedures are periodically reviewed and annually certified by the Process Supervisor as current and accurate.  The procedures are kept current and accurate by revising them as necessary to reflect changes made through the Management of Change process. 
   In addition, safe work practices have been developed and implemented for employees and contractors to control hazards during operations (e.g., lockout/tagout, confined space entry, opening process equipment or piping).  This information, along with written operating procedures, is readily available to operators in the process unit and for other personnel to use as necessary to safe 
ly perform their job tasks. 
   E.    Training 
   To complement the written procedures for process operations, Marathon has implemented a comprehensive and effective training program for all employees involved in operating a process.  The program, including initial training, refresher training and documentation, is intended to help employees understand the nature and problems arising from process operations and increase employee awareness with respect to the hazards particular to a process.  Each new employee and each employee operating a newly assigned process is trained in an overview of the process and in the operating procedures for the unit.  The training includes emphasis on the safety and health hazards, emergency operations, and safe work practices applicable to the employee's job assignment.  In addition, all operators periodically receive refresher training on the operating procedures to ensure that their skills and knowledge are maintained at an acceptable level.  This refresher t 
raining is conducted at least once every three years.  All of this training is documented for each operator, including the means used to verify that the operator understood the training. 
   F.    Contractors 
   Contractors are used to supplement the work force during periods of increased maintenance or construction activities.  Procedures are in place to ensure that contractors hired can accomplish the desired job tasks without compromising the safety and health of Marathon employees, contractor employees, or the facility.  The contractor is required to ensure that its employees are trained on performing the job safely, of the hazards related to the job, and applicable provisions of the emergency action plan.  This is accomplished by hiring only contractors on the Approved Contractor List.  To be kept on such list, the contractor must be familiar with the facility processes, information about safety and health hazards, emergency response plan requirements, and safe work practices.  The cont 
ractor is also required to document the training, to advise Marathon personnel of hazards found by the contractor employees, and to report all accidents, injuries, illnesses and near misses to plant personnel.  Each contractor working at the facility is monitored and evaluated at least annually to ensure that the contractor fulfills the safety obligations.  
   G.    Pre-Startup Safety Review (PSSR) 
   A PSSR is conducted for any new facility or facility modification that requires a change in the process safety information.  The purpose of the PSSR is to ensure that safety features, procedures, personnel, and equipment are appropriately prepared for startup prior to placing the equipment into service.  This review provides one additional check to make sure:  
       1)     that construction is in accordance with the design specifications;  
       2)    that safety, operating, maintenance and emergency procedures are in place and are adequate;  
       3)     that, for a new facility, a PHA has been performed and reco 
mmendations resolved;  
       4)     that, for a modified facility, the requirements of the Management of Change program have been met; and  
       5)     that training of each employee involved in operating an affected process has been completed and documented.   
   The PSSR team uses a pre-approved checklist to verify all aspects of readiness.  
   H.    Mechanical Integrity 
   Marathon has a well-established program to ensure that equipment such as pressure vessels and storage tanks, piping systems, relief and vent systems, controls, pumps and compressors, and emergency shutdown systems is designed, constructed, installed, and maintained to minimize the risk of accidental releases.  The program primarily consists of developing written procedures, conducting maintenance training, performing inspections and tests, identifying and correcting deficiencies, and applying quality assurance measures. 
   Marathon management has chosen to follow the guidelines set forth in the Marathon Oil Company Worldwide Productio 
n Corrosion Monitoring Program, American Petroleum Institute's Recommended Practice 510, and applicable standards set forth by the American Society of Mechanical Engineers.  Maintenance personnel receive training on 1) an overview of the process and its hazards, 2) applicable maintenance procedures, and 3) certification for employees conducting nondestructive testing, welding, etc.  Written procedures  ensure that work is performed in a consistent manner and provide a basis for training.  Inspections and tests are performed and documented to help ensure that equipment functions as intended and to verify that equipment is within acceptable limits (e.g., adequate wall thickness for pressure vessels).  If a deficiency in equipment is identified, it will be corrected before further use. 
   Another integral part of the mechanical integrity program is quality assurance.  Marathon incorporates quality assurance measures into equipment purchases, installation and repairs to assure consistency w 
ith design specifications and manufacturer's instructions.  This practice also applies to contractor supplied equipment and parts.  
   I.    Safe Work Practices 
   Marathon has long standing safe work practices in place to ensure worker and process safety.  Examples of these include: 1) control of the entry/presence/exit of support personnel, 2) a lockout/tagout procedure to ensure isolation of energy sources for equipment undergoing maintenance, 3) a procedure for safe removal of hazardous substances before process piping or equipment is opened, 4) a permit and procedure to control spark producing activities (i.e., hot work), and 5) a permit and procedure to ensure that adequate precautions are in place before entry into a confined space.  These procedures, along with training of affected personnel, form a system to ensure that operations and maintenance activities are performed safely. 
   J.    Management of Change 
   Marathon has a comprehensive system to manage changes to all covered process 
es.  This system requires that changes to items such as process equipment, chemicals, technology,  operating procedures, and other changes be properly reviewed and authorized before being implemented.  The system not only addresses the permanent changes, but also includes emergency and temporary changes.  All these changes are reviewed to ensure that adequate controls are in place to manage any new hazards and to verify that existing controls have not been compromised by the changes.  Affected chemical hazard information, process technology, equipment information, and procedures are updated to incorporate these changes.  A Management of Change Request form is used to facilitate the necessary reviews, approvals, and updates. 
   K.    Incident Investigation 
   Marathon has established and implemented a procedure to investigate all incidents that resulted in, or reasonably could have resulted in, personal injury or death, significant property damage, or release of contaminants which caused or  
could have caused significant environmental damage.  The investigations are initiated as promptly as possible, but no later than 48 hours following the incident.  The goal of each investigation is to determine the root cause of the incident and to develop corrective actions to prevent a recurrence or a similar incident.  The investigation team documents its findings, develops recommendations to prevent recurrence, and forwards these results to management for resolution.  Corrective actions taken in response to the investigation team's findings and recommendations are tracked until they are complete.  The final resolution of each finding or recommendation is documented and the investigation results are reviewed with all affected employees (including contractors).  Incident investigation reports are retained for at least five years. 
   L.    Compliance Audits 
   Marathon conducts audits to determine whether the procedures and practices required by the PSM and accident prevention programs are  
adequate and being implemented.  Compliance audits are conducted at least once every three years.  The audit team develops findings that are forwarded tomanagement for resolution.  Corrective actions taken in response to the audit team's findings are tracked until they are complete.  The final resolution of each finding is documented, and the two most recent audit reports are retained on file. 
V.    Chemical-Specific Prevention Steps 
Facility processes have hazards that must be managed to ensure continued safe operation.  The following is a description of existing safety features applicable to prevention of accidental releases of regulated substances in the facility. 
   A.    Universal Prevention Activities 
   The accident prevention program summarized previously is applied to the entire facility.  Collectively, these prevention program activities help prevent potential accident scenarios that could be caused by equipment failures and human errors. 
   B.    Specialized Safety Features 
   The faci 
lity has safety features in many areas to help: 1) quickly detect a release, 2) contain/control a release, and 3) reduce the consequences of (mitigate) a release.  The following types of safety features are used in the plant: 
       a.    Release Detection  
               Fixed hydrogen-sulfide monitors with alarms 
       b.    Release Containment/Control 
               Atmospheric relief devices 
               Process relief valves that discharge to a flare to capture and burn episodic releases 
               Manual and automatic valves to allow isolation of the process 
               Automatic shutdown systems 
               Seconday power source 
               Redundant equipment and instrumentation 
       c.    Release Mitigation 
               Fire suppression and extinguishing system 
               Plant firewater system 
               Dikes to contain liquid releases 
VI.    Five-year Accident History 
The facility has an excellent record of accident prevention over the past five years.  There have been no accidental releases of regulated substances with off-site impacts in the past five years. 

II.    Emergency Response Program Information 
Marathon has developed and implemented a written emergency response program 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 potentially resulting from a fire or explosion, severe weather, environmental spill,or pipeline failure.  The procedures address all aspects of emergency response, including proper first aid and medical treatment, evacuation plans and accounting for personnel, notification of local emergency response agencies and the public, and post incident cleanup, reporting and recordkeeping requirements.  The emergency response program is updated when necessary based on factors such as modifications made to the plant process or operating procedures, or a change in the communication procedures. 
The emergency response program is coordinated with the local emergency response and government officials.  The facility has round-the-clo 
ck communication capability with appropriate local emergency planning committee (LEPC) officials and emergency response organizations (e.g., fire department).  This provides a means of notifying the public of an incident, if necessary, as well as facilitating quick response to an incident.  In addition to meetings with the LEPC, the facility conducts periodic emergency drills that involve the local community and emergency response organizations. 
VIII.  Planned Changes to Improve Safety 
All findings from the previous PHAs, incident investigations, and safety audits have been successfully resolved.  Marathon personnel will continue to conduct PHAs, safety audits, and incident investigations as applicable to continuously improve the worker and public safety.
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