Marathon Oil Company - Stoney Point Gas Plant - Executive Summary
Risk Management Plan |
Stoney Point Gas Plant
Marathon Oil Company
Hillsdale County, Michigan
I. Accidental Release Prevention and Response Policies
Marathon Oil Company's Stoney Point Gas Plant (SPGP) 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 Oil Company's policy is to implement reasonable measures to prevent foreseeable releases of regulated substances. However, if a release does occur, trained gas plant personnel will respond to effectively control, contain and mitigate the release.
II. Description of the Stationary Source and Regulated Substances
Stoney Point Gas Plant, located near Jonesville, Michigan, operates processes to remove liquids from natural gas. The plant has several regulated flammables, such as ethane, butane,
propane, and pentane. The plant does not have any regulated toxic substances with an amount that is above the threshold quantity specified in 40 CFR 68. Although the inlet gas contains approximately 350 ppm of hydrogen sulfide (H2S), which is removed in an amine unit, the total plant inventory of H2S is well below the threshold quantity. Therefore, H2S at the SPGP is not considered a regulated toxic substance under RMP rule.
III. Offsite Consequence Analysis Results
The worst case scenario (WCS) associated with a release of flammable substances at the SPGP is a vapor cloud explosion (VCE) involving the full inventory of the largest storage tank containing natural gas liquid (NGL). The tank has a capacity of 30,000 gal, or 150,000 lbs of NGL. This inventory is assumed to release and ignite, resulting in a VCE. The maximum distance to the 1-psi endpoint for this WCS is 0.43 miles. Although there are numerous controls at the SPGP to prevent such releases and to mitigate their co
nsequences, no credit for passive mitigation measures was taken into account in evaluating this WCS.
The alternate release scenario (ARS) for flammable substance at the SPGP is a VCE from the release of natural gas resulting from the failure of gas handling equipment, such as a compressor. Typically, a gas release at SPGP is expected to be isolated by the operators within 15 minutes. However, for the purpose of this study, it is assumed that the release continued for 30 minutes, releasing 84,000 standard cubic feet, or 5400 lbs, of natural gas. The maximum distance to the 1-psi endpoint for this event is 0.1 mile. Although allowed by the regulations to be considered, many passive mitigation measures implemented at the SPGP were not credited in developing the ARS. This event was selected as a practical scenario for use in emergency planning and response.
IV. General Accident Release Prevention Program
The accident prevention program in place at SPGP is summarized in the followi
ng. Because the SPGP 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
The SPGP ensures its employees participate in all development, review and implementation aspects of process safety management 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 document
ed in an employee participation plan that is maintained at the plant.
B. Process Safety Information
The SPGP keeps 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 departments within the gas plant and region office are assigned responsibility for maintaining up-to-date process safety information. "Stoney Point Gas Plant Process Safety Information Document" summarizing the reference documents and their location is readily available to provide employees with an overview of process safety information and to help locate process reference documents for detailed information.
Chemical-specific information, including exposure hazards and emergency response/exposure treatment considerations, is provided in material safety data sheets (MSDS). The SPGP maintains on file process flow diagrams, a description of the proce
ss, 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. The SPGP ensures that the process is maintained within these limits using process controls and monitoring instruments, highly trained personnel, and protective instrument systems (e.g., automated shutdown systems).
The SPGP also maintains technical documents that provide information about the design and construction of process equipment. 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, 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 process are not compromised.
C. Process Hazard Analysis (PHA)
The SPGP 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 SPGP primarily uses the what-if analysis technique to perform these evaluations. The analyses are conducted using a team of people who have operating and maintenance experience as well as engineering expertise. This team identifies and evaluates hazards of the process as well as accident prevention and mitigation measures, and the team makes suggestions for additional prevention and/or mitigation measures when the team believes such measures are necessary.
The PHA team f
indings are forwarded to local and regional 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 revalidate 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 management for consideration, and the final resolution of the findings is documented and retained.
D. Operating Procedures
The SPGP maintains operating procedures and manuals that address various modes of process operations, such as unit startup, normal operations, norma
l shutdown, temporary operation, emergency operations, emergency shutdown, and initial startup of a new process. The procedures and manuals include 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 Production Foreman 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, the SPGP has developed and implemented safety work practices for employees and contractors to control hazards during operations, such as, lockout/tagout, confined space entry, opening process equipment or piping. This informat
ion, along with written operating procedures, is readily available to operators in the process unit and for other personnel to use as necessary to safely perform their job tasks.
To complement the written procedures for process operations, the SPGP 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 rec
eive refresher training on the operating procedures to ensure that their skills and knowledge are maintained at an acceptable level. This refresher training 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.
The SPGP uses contractors to supplement its work force during periods of increased maintenance or construction activities. The SPGP has procedures in place to ensure that contractors hired can accomplish the desired job tasks without compromising the safety and health of Marathon employees, contract employees, or the facility. The contractor is required to ensure that contract 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 contract
or must: 1) provide employee injury/ illness statistics, which must meet levels acceptable to Marathon; and 2) be familiar with the SPGP processes, information about safety and health hazards, emergency response plan requirements, and safe work practices. Additionally, each contractor new to the plant is given an overview in safety orientation prior to entering the gas plant. The contractor is also required to document the training, to advise the SPGP of hazards found by the contractor, and to report all accidents, injuries, illnesses and near misses to plant personnel. Each contractor working at the SPGP is monitored and evaluated at least annually to ensure that the contractor fulfills the safety obligations.
G. Pre-startup Safety Reviews
The SPGP conducts a pre-startup safety review for any new facility or facility modification that requires a change in the process safety information. The purpose of the pre-startup safety review 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 recommendations resolved; 4) that, for a modified facility, the requirements of the Management of Change have been met; and 5) that training of each employee involved in operating an affected process has been completed and documented. The pre-startup safety review team uses a pre-approved checklist to verify all aspects of readiness.
H. Mechanical Integrity
The SPGP 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, insta
lled, 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.
The SPGP management has chosen to follow the guidelines set forth in the Marathon Oil Company Worldwide Production Corrosion Monitoring Program and American Petroleum Institute's Recommended Practice 510. 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 tests, 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, corrective measures and actions will be taken.
Another integral part of the mechanical integrity program is quality assurance. The SPGP incorporates quality assurance measures into equipment purchases, installation and repairs to assure consistency with design specifications and manufacturer's instructions. This practice also applies to contractor supplied equipment and parts.
I. Safe Work Practices
The SPGP 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 adequa
te 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
The SPGP has a comprehensive system to manage changes to all covered processes. 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 checklist, Management of Change Request form, is u
sed to facilitate the necessary reviews, approvals, and updates.
K. Incident Investigation
The SPGP has established and implemented a procedure to investigates all incidents that resulted in, or reasonably could have resulted in, personal injury, illness 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 a 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 recommend
ation 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
The SPGP conducts audits to determine whether the procedures and practices required by the process safety management and accident prevention program are adequate and being implemented. Compliance audits are conducted at least once every three years. The audit team develops findings that are forwarded to the management 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
The processes at the SPGP have hazards that must be managed to ensure continued safe operation. The following is a description of existing safety features applicable to prevention of accidenta
l releases of regulated substances in the facility.
A. Universal Prevention Activities
The accident prevention program summarized previously is applied to the entire SPGP. 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 SPGP 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
Hydrocarbon detectors with alarms
Fire detectors with alarms
H2S detectors 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
n systems and keyed bypass for specific process parameters (e.g., pressure)
Excess flow device
Redundant equipment and instrumentation
c. Release Mitigation
Fire suppression and extinguishing system
Dikes to contain liquid releases
A fully equipped spill trailer containing spill abatement equipment and materials such as booms, absorbent, boat, road signs, etc.
VI. Five-year Accident History
The SPGP has an excellent record of accident prevention over the past five years. There have been no accidental releases of regulated substances in the past five years that are subject to the reporting requirements in 40 CFR 68.
VII. Emergency Response Program Information
The SPGP 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, and equipment 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 modification made to the plant process or operating procedures, or change in the communication procedures.
The emergency response program for the SPGP is coordinated with the Hillsdale County local emergency planning committee (LEPC), which consists of local emergency response officials, state and local government officials, and industry representatives. The SPGP has around-the-clock communication capability with appropriate LEPC officials and emergency response organizations (e.g., fire department). This provides a means of notif
ying the public of an incident, if necessary, as well as facilitating quick response to an incident. In addition to meetings with the LEPC, the SPGP conducts periodic emergency drills that involve the LEPC and emergency response organizations.
VIII. Planned Changes to Improve Safety
All findings from the previous PHAs and safety audits have been successfully resolved. The SPGP will continue to conduct PHAs, safety audits, and incident investigations as applicable to continuously improve the worker and public safety.