Walker Creek Gas Plant - Executive Summary |
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WALKER CREEK GAS PLANT RISK MANAGEMENT PLAN: EXECUTIVE SUMMARY ACCIDENTAL RELEASE PREVENTION AND RESPONSE POLICIES The Walker Creek Gas Plant 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 processes. Our policy is to implement reasonable controls to prevent foreseeable releases of regulated substances. However, if a release does occur, gas plant trained personnel will respond to control and contain the release. DESCRIPTION OF THE STATIONARY SOURCE AND REGULATED SUBSTANCES The Walker Creek Gas Plant, located in Taylor, Arkansas, operates a variety of processes to produce petroleum products (e.g., natural gas, ethane, propane, butane) from natural gas. The Walker Creek Gas Plant has several regulated flammables, such as ethane, propane and butane. OFFSITE CONSEQ UENCE ANALYSIS RESULTS The WCS associated with a release of flammable substances in Program Level 2 processes at the gas plant is a vapor cloud explosion (VCE) involving the full inventory of the largest storage tank containing natural gas liquids(NGL's). The maximum vessel inventory of 220,000 pounds is assumed to release and ignite, resulting in a VCE. The maximum distance to the 1-psi endpoint for this WCS is 0.50 miles. Although we have numerous controls to prevent such releases and to manage their consequences, no credit for passive mitigation measures was taken into account in evaluating this WCS. The ARS for flammable substances at the gas plant is a VCE resulting from the release of NGL's from the overfilling of a the storage vessel. The maximum distance to the 1-psi endpoint for this event is 0.14 miles. This event was selected as being a practical scenario for use in emergency planning and response. GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM The followi ng is a summary of the accident prevention program in place at the plant. The gas plant process is regulated by the Environmental Protection Agency's (EPA's) risk management program (RMP) regulation. This summary addresses the elements of the Walker Creek Gas Plant's accident prevention program and describes the management system in place to implement the accident prevention program. Process Safety Information The Walker Creek Gas Plant keeps a variety of technical documents that are used to help maintain safe operation of the processes. These documents address chemical properties and associated hazards, limits for key process parameters and specific chemical inventories, and equipment design basis/configuration information. Personnel at the gas plant are assigned responsibility for maintaining up-to-date process safety information. Chemical-specific information, including exposure hazards and emergency response/ exposure treatment considerations, is provided in material safety data sheets (MSDSs). This information is supplemented by documents that specifically any known hazards associated with the inadvertent mixing of chemicals. For specific process areas, the gas plant has documented safety-related limits for specific process parameters (e.g., temperature, level, composition) in the Walker Creek Gas Plant Operating Procedures Manual. The gas plant 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 gas plant also maintains numerous technical documents that provide information about the design and construction of process equipment. This information includes materials of construction, design pressure and temperature ratings of equipment. This information, in combination with written procedures and trained personnel, provides a basis for establishing inspection and maintenance activities, as well as for evaluating proposed process and facility changes to ensure that safety features in the process are not compromised. Process Hazard Analysis (PHA) The Walker Creek Gas Plant has a comprehensive program to help ensure that hazards associated with the various processes are identified and controlled. Within this program, each process is systematically examined to identify hazards and ensure that adequate controls are in place to manage these hazards. The Walker Creek Gas Plant primarily uses the Checklist analysis technique to perform these evaluations. Checklist analysis, performed by trained and knowledgeable personnel is recognized as an extremely thorough hazard evaluation technique. The analyses are conducted by personnel who have operating and maintenance experience as well as engineering expertise. The PHA personnel identify and evaluate hazards of the process as well as accident prevention and mitigation measures, and makes suggestions for additional preventi on and/or mitigation as necessary. The PHA findings are forwarded to local and corporate management for resolution. Implementation of mitigation options in response to PHA findings is based on a relative risk ranking assigned during the PHA process. This ranking helps ensure that potential accident scenarios assigned the highest risk receive immediate attention. All approved mitigation options in response to PHA findings are tracked until they are completed. The final resolution of each finding is documented and retained. To help 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 5 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 PHA fi ndings are forwarded to management for consideration, and the final resolution of the findings is documented and retained. Operating Procedures The Walker Creek Gas Plant maintains written procedures that address various modes of process operations, such as (1) unit startup, (2) normal operations, (3) temporary operations, (4) emergency shutdown, (5) normal shutdown, and (6) initial startup of a new process. These procedures can be used as a reference by experienced operators and provide a basis for consistent training of new operators. These procedures are periodically reviewed at least annually to verify completeness and accuracy. In addition, the Walker Creek Gas Plant Operating Procedures Manual also contains a section pertaining to the consequences of deviation which provides guidance on how to respond to upper or lower limit exceedances for specific process or equipment parameters. This information, along with written operating procedures, is readily available to ope rators in the process unit and for other personnel to use as necessary to safely perform their job tasks. Training To complement the written procedures for process operations, the Walker Creek Gas Plant has implemented a comprehensive training program for all employees involved in operating a process. New employees receive basic training in gas plant operations if they are not already familiar with such operations. After successfully completing this training, a new operator is paired with a senior operator to learn process-specific duties and tasks. After operators demonstrate (e.g., through oral tests, skills demonstration) having adequate knowledge to perform the duties and tasks in a safe manner on their own, they can work independently. In addition, all operators periodically will be re-certified on the operating procedures to ensure that their skills and knowledge are maintained at an acceptable level. This re-certification is conducted at least every 3 years. All of th is training is documented for each operator, including the means used to verify that the operator understood the training. Maintenance The Walker Creek Gas Plant has well-established practices and procedures to maintain pressure vessels, piping systems, relief and vent systems, controls, pumps and compressors, and emergency shutdown systems in a safe operating condition. The basic aspects of this program include: (1) conducting training, (2) developing written procedures, (3) performing inspections and tests, (4) correcting identified deficiencies, and (5) applying quality assurance measures. In combination, these activities form a system that maintains the integrity of the process. Maintenance personnel receive training on (1) an overview of the process, (2) safety and health hazards, (3) applicable maintenance procedures, (4) emergency response plans, and (5) applicable safe work practices to help ensure that they can perform their jobs in a safe manner. Written procedure s help ensure that work is performed in a consistent manner and provide a basis for training. Inspections and tests are performed to help ensure that equipment functions as intended and to verify that equipment is within acceptable limits. Safe Work Practices The Walker Creek Gas Plant has long-standing safe work practices in place to help ensure worker and process safety. Examples of these include: (1) a lockout/tagout procedure to ensure isolation of energy sources for equipment undergoing maintenance, (2) a permit and procedure to control spark-producing activities (i.e., hot work), and (3) a permit and procedure to ensure that adequate precautions are in place before entry into a confined space. These procedures (and others), along with training of affected personnel, form a system to help ensure that operations and maintenance activities are performed safely. Incident Investigation The Walker Creek Gas Plant promptly investigates all incidents that resulted in, or reasonably could have resulted in, a fire/explosion, major property damage, environmental loss, or personal injury. The goal of each investigation is to determine the facts and develop corrective actions to prevent a recurrence of the incident or a similar incident. The investigation team documents its findings, develops recommendations to prevent a recurrence, and forwards these results to gas plant 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 employees (including contractors) who could be affected by the findings. Incident investigation reports are retained for at least 5 years so that the reports can be reviewed during future PHAs and PHA revalidations. Compliance Audits To help ensure that the accident prevention program is functioning properly, the Walker Creek Gas Plant periodically conducts an audit to determine whether the procedures and practices required by the accident prevention program are being implemented. Compliance audits are conducted at least every 3 years. Both hourly and staff personnel will participate in the audit. The audit team develops findings that are forwarded to gas plant 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. FIVE-YEAR ACCIDENT HISTORY The Walker Creek Gas Plant has an excellent record of accident prevention over the past 5 years. Due to the active involvement of plant management and personnel in the accident prevention programs described above there have been no accidental releases during this period. EMERGENCY RESPONSE PROGRAM INFORMATION The Walker Creek Gas Plant maintains a w ritten emergency response program, 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 accidentally released. The procedures address all aspects of emergency response, including proper first aid and medical treatment for exposures, evacuation plans and accounting for personnel after an evacuation, notification of local emergency response agencies and the public if a release occurs, and post-incident cleanup and decontamination 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 to perform their specific emergency response duties. The emergency response program is updated when necessary based on modifications made to gas plant processes or other Walker Creek Gas Plant facilities. The overall emergency response program for the Walker Creek Gas Plant is coordinated with the Columbia County LEPC. The Walker Creek Gas Plant has around-the-clock communications capability with appropriate 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. PLANNED CHANGES TO IMPROVE SAFETY The Walker Creek Gas Plant resolves all findings from PHAs, some of which result in modifications to the process. The following types of changes are planned over the next few years in response to PHA, safety audit, and incident investigation findings: 7 Installation of additional overpressure protection plant equipment 7 Revisions to personnel training programs 7 Revisions to plant shutdown system |