Shackelford Gas Plant - Executive Summary |
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EXECUTIVE SUMMARY ACCIDENTAL RELEASE PREVENTION AND RESPONSE POLICIES The Continental Natural Gas Shackelford 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 Shackelford gas plant, located in Shackelford, Texas, operates a variety of processes to produce petroleum products (e.g., natural gas, propane, butane, condensate) from natural gas. The Shackelford gas plant has several regulated flammables, such as propane and butane. There are no regulated toxic substances at the Shackelford fac ility. OFFSITE CONSEQUENCE ANALYSIS RESULTS The worst-case scenario (WCS) associated with a release of flammable substances in Program Level 3 processes at the gas plant is a vapor cloud explosion (VCE) involving the full inventory of the largest storage tank containing 30,000 gallons (125,2000 lb). A written procedure is in place to limit the storage inventory to 90% of the maximum tank capacity; therefore, the reduced inventory is assumed to release and ignite, resulting in a VCE. The maximum distance to the 1-psi endpoint for this WCS is 0.4 miles. Although numerous controls are in place to prevent such releases and to manage their consequences, no credit for passive mitigation measures was taken into account in evaluating this WCS. The Alternative Release Scenario (ARS) for flammable substances at the Shackelford gas plant is a VCE resulting from the release of 9500 gallons (39,600 lb) from a product loading pump. The release is expected to be isolated by the operators within 15 minutes (active mitigation). The maximum distance to the I-psi endpoint for this event is 0.27 miles. This event was selected as being a practical scenario for use in emergency planning and response. Figure 1-1 graphically presents the hazard assessment results for the flammable WCS and ARS events. GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM The following is a summary of the accident prevention program in place at the Shackelford plant. Because processes at the gas plant that are regulated by' the Environmental Protection Agency's (EPA's) risk management program (RAMP) regulation are 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. Employee Participation The Shackelford gas plant encourages employees to participate in all facets of process safety management and acciden t prevention. Examples of employee participation range from updating and compiling technical documents and chemical information to participating as a member of a process hazard analysis (PHA) 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 participation plan that is maintained at the gas plant and addresses each accident prevention program element. In addition, the gas plant has a number of initiatives under way which address process safety and employee safety issues. These initiatives include forming teams to promote both process and personal safety. The teams typically have members from various areas of the plant, including operations, maintenance, engineering, and plant management. Process Safety Information The Shackelford gas plant keeps a variety of technical documents that are used to help maintain safe opera tion 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. Specific departments within the gas plant are assigned responsibility for maintaining up-to-date process safety information. A table summarizing the reference documents and their location is readily available as part of the written employee participation plan to help employees locate any necessary process safety information. Chemical-specific information, including exposure hazards and emergency response/exposure treatment considerations, is provided in material safety data sheets (MSDSs). The gas plant ensures that the process is maintained within acceptable 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 p rovide information about the design and construction of process equipment. This information includes materials of construction, design pressure and temperature ratings, and electrical rating 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 Shackelford 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 Shackelford gas plant primarily uses the hazard and operability (HAZOP) analysis technique to perform these evaluations. HAZOP analysis is recognized as one of the most s ystematic and thorough hazard evaluation techniques. 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 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 by the PHA team. This ranking helps ensure that potential accident scenarios assigned the highest risk receive immediate attention. 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 help ensure that the process controls and/or process hazards do n ot 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 management for consideration, and the final resolution of the findings is documented and retained. Operating Procedures The Shackelford 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 and annually certi fied 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 Shackelford plant maintains written operating procedures, which are readily available to operators 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 Shackelford 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 tests, skills demonstration) adequate knowledge to perform the duties and tasks in a safe manner on their own, they can work independently. 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 training is conducted at least every three years. All of this training is documented for each operator, including the means used to verify that the operator understood the training. Contractors The Shackelford gas plant uses contractors to supplement its workforce during periods of increased maintenance or construction activities. Because some contractors work on or near process equipment, the gas plant has procedures in place to ensure that contractors (1) perform their work in a safe manner, (2) have the appropriate knowledge and skills, (3) are aware of the hazards in their workplace, (4) understand what they should do in the event of an emergency, (5),understand and follow site safety rules, and (6) inform gas plant personnel of any hazards that they find during their wo rk. This is accomplished by providing contractors with (1) a process overview, (2) information about safety and health hazards, (3) emergency response plan requirements, and (4) safe work practices prior to their beginning work. In addition, the Shackelford gas plant evaluates contractor safety programs and performance during the selection of a contractor. Gas plant personnel periodically monitor contractor performance to ensure that contractors are fulfilling their safety obligations. Pro-Startup Safety Reviews (PSSRs) The Shackelford gas plant conducts a PSSR 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 construction is in accordance with the design specifications and that all supporting system s are operationally ready. The PSSR review team uses checklists to verify all aspects of readiness. A PSSR involves field verification that accident prevention program requirements are properly implemented. Mechanical Integrity The Shackelford 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 mechanical 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 procedures 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 (e.g., adequate wall thickness for pressure vessels). If a deficiency is identified, employees will correct the deficiency before placing the equipment back into service (if possible), or a management of change team will review the use of the equipment and determine what actions are necessary to ensure the safe operation of the equipment. Another integral part of the mechanical integrity program is quality assurance. The Shackelford gas plant incorporates quality assurance measures into equipment purchases and repairs. This helps ensure that new equipment is suitable for its intended use and that proper materials and spare parts are used when repairs are mad e. Safe Work Practices The Shackelford gas plant has long-standing safe work practices in place to help 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 sparkproducing 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 (and others), along with training of affected personnel, form a system to help ensure that operations and maintenance activities are performed safely. Management of Change The Shackelford gas plant has a comprehensive system to manage changes to all covered processes. This system requires that changes to items such as process equipment, chemica ls, technology (including process-operating conditions), procedures, and other facility changes be properly reviewed and authorized before being implemented. Changes are reviewed to (1) ensure that adequate controls are in place to manage any new hazards, and (2) verify that existing controls have not been compromised by the change. Affected chemical hazard information, process operating limits, and equipment information, as well as procedures, are updated to incorporate these changes. In addition, operating and maintenance personnel are provided any necessary training on the change. Incident Investigation The Shackelford gas plant promptly investigates all incidents that resulted in, or reasonably could have resulted in, a fire/explosion, toxic gas release, 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 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 five years so that the reports can be reviewed during future PHAs and PHA re-validations. Compliance Audits To help ensure that the accident prevention program is functioning properly, the Shackelford 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 three years. Both hourly and staff personnel participate as audit team members. 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. CHEMICAL-SPECIFIC PREVENTION STEPS The processes at the Shackelford gas plant have hazards that must be managed to ensure continued safe operation. Following is a description of existing safety features applicable to prevention of accidental releases of regulated substances in the facility. Universal Prevention Activities The accident prevention program summarized previously is applied to all RMP-covered processes at the Shackelford gas plant. Collectively, these prevention program activities help prevent potential accident scenarios that could be caused by equipment failures and human errors. Specialized Safety Features The Shackelford gas plant has safety features on many units to help (1) contain/control a release, (2) quickly detect a release, and (3) reduce the consequences of (mitigate) a relea se. The following types of safety features are used in the covered processes: Release Detection 1 . Hydrocarbon detectors with alarms Release Containment/Control 1. Process relief valves that discharge to a flare to capture and incinerate episodic releases 2. Valves to permit isolation of the process (manual or automated) 3. Automated shutdown systems for specific process parameters (e.g., high temperature) 4. Curbing or diking to contain liquid releases 5. Redundant equipment and instrumentation (e.g., uninterruptible power supply for process control system, backup firewater pump) 6. Atmospheric relief devices Release Mitigation 1. Fire suppression and extinguishing systems 2. Deluge system for specific equipment 3. Trained emergency response personnel 4. Personal protective equipment (e.g., chemical protective clothing, self-contained breathing apparatus) 5. Blast-resistant buildings to help protect control systems and personnel FIVE-YEAR ACCIDENT HISTORY The Shackelford gas plant has an excellent record of accident prevention over the past five years. There have been no off-site accidents within this time period. EMERGENCY RESPONSE PROGRAM INFORMATION The Shackelford gas plant maintains a written emergency response program that 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 ad dress 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. When necessary, the emergency response program is updated based on modifications made to gas plant processes or other Shackelford gas plant facilities. The emergency response program changes are administered through the MOC process, which includes informing and/or training affected personnel in the changes. The overall emergency response program for the Shackelford gas plant is coordinated with the Shackelford, Oklahoma Local Emergency Planning Committee (LEPC). This coordination includes periodic meetings of the committee, which includes local emergency response officials, local government officials, and industry representatives. The Shackelford gas plant has around-the-clock communications capability with appropriate LE PC 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 periodic LEPC meetings, the Shackelford gas plant conducts periodic emergency drills that involve the LEPC and emergency response organizations, and the gas plant provides annual refresher training to local emergency responders regarding the hazards of regulated substances in the gas plant. PLANNED CHANGES TO IMPROVE SAFETY The Shackelford gas plant resolves all findings from PHAs, some of which may result in modifications to the process. At the current time, no changes are planned over the foreseeable future. |