Exxon Billings Refinery - Executive Summary

| Accident History | Chemicals | Emergency Response | Registration | Source | Executive Summary |

The Exxon Billings Refinery has a long-standing commitment to worker and public safety and protecting 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 our processes.  Our objective is to implement reasonable controls to prevent foreseeable releases of regulated substances.  However, if a release does occur, our trained personnel will respond to control, contain and mitigate the release. 
In 1991, Exxon modified its safety programs by adopting a concept of structured safety management systems entitled Operations Integrity Management Systems (OIMS).  In 1997, Lloyd's Register Quality Assurance reviewed OIMS and evaluated it against the international standard for Environmental Management Systems (ISO 14001) to determine if OIMS meets the requirements of ISO 14001.  Afte 
r an extensive review which included a number of facility audits, Lloyd's concluded that the "environmental components of OIMS are consistent with the intent and meet the requirements of the ISO 14001 Environmental Management Systems Standard."  They went on to say, "We further believe Exxon to be among the industry leaders in the extent to which environmental management considerations have been integrated into its ongoing business processes." 
Another example of Exxon's commitment was establishing a hydrofluoric (HF) acid steering group to coordinate the release prevention and emergency response efforts of its three HF alkylation units worldwide.  The group established best practices for the operation and maintenance of the units and led efforts for a consistent approach to HF acid release response through enhanced detection and automatic initiation of a water wall mitigation system. 
The Exxon Refinery, located near Billi 
ngs, Montana, U.S.A., operates a variety of processes to produce petroleum products (e.g., propane, butane, gasoline products, jet fuels, diesel fuels, asphalt and coke) from raw crude oil.  The refinery has several regulated flammables, such as propane, butane, etc.  In addition, the refinery uses and/or processes anhydrous ammonia, aqueous ammonia (>20%), hydrofluoric (HF) acid and hydrogen sulfide, which are also regulated substances.  Even though anhydrous ammonia, aqueous ammonia (>20%), and hydrogen sulfide are present in amounts less than the RMP threshold quantities, we treat them in the same way by applying the accidental release prevention and the emergency response programs.  For the purpose of the Risk Management Plan, Exxon Billings Refinery considered all covered processes to be Program Level 3. 
The hazard assessments used the EPA supplied "look up tables" which have been incorporated into the computer program supplied by NOAA. This program is  
called RMP Comp (version 1.06).  This program uses all the parameters required by the RMP rule for both worst case scenarios (WCS) and alternative release scenarios (ARS). 
The WCS associated with toxic substances in Program Level 3 processes at the refinery is a catastrophic failure of the hydrofluoric (HF) acid de-inventory drum in the Alkylation Unit which causes an off-site impact.  Although we have numerous controls to prevent such releases and to manage their consequences, no credit for mitigation measures was taken into account in evaluating this scenario. 
The alternative release scenario (ARS) for HF acid is a pump seal leak in the Alkylation Unit.  The ARS has an off-site impact.  No mitigation measures were taken into account in evaluating this scenario that is to be used for emergency response planning.  However, the refinery's accidental release prevention and emergency response programs provide multiple levels of protection that would prevent this ARS from having off-site 
Accidental release prevention includes: 
7 Use of tandem seal or seal-less pumps in HF acid service with instrumentation to detect a seal leak 
Emergency response measures include:  
7 HF acid detectors that are located throughout the HF acid area to notify refinery personnel if HF acid has been released to the atmosphere 
7 TV camera surveillance that assists refinery personnel in detecting and responding to a potential leak 
7 An 11,000 gpm water wall mitigation system that is automatically initiated by the HF acid detectors 
7 Remote operated isolation valves that are strategically located to quickly and safely isolate an HF acid leak 
7 Remote operated de-inventory system that is triggered by refinery personnel to remove HF acid from the operating equipment to a separate storage drum away from the unit piping and vessels. 
7 Highly trained operators and emergency response teams 
The WCS associated with a release of flammable substances in Program Level 3 processes at the r 
efinery is a vapor cloud explosion (VCE) involving the full inventory of the largest storage sphere (i.e., pressurized storage vessel) containing butane in our light ends storage and handling area.  Although we have numerous controls to prevent such releases and to manage their consequences, no credit for mitigation measures was taken into account in evaluating this WCS.  This WCS has an off-site impact. 
The ARS for flammable substances at the refinery is a liquefied petroleum gas (LPG) pipe leak in our light ends storage and handling area.  The ARS has an off-site impact.  No mitigation measures were taken into account in evaluating this scenario that is to be used for emergency response planning. 
The following is a summary of the general accident prevention program in place at the Exxon Billings Refinery.  EPA's Program Level 3 prevention requirements were implemented because some processes at the refinery meet Program Level 3 cr 
iteria and are also subject to the OSHA Process Safety Management (PSM) standard.  In addition, Exxon Corporation has implemented Operations Integrity Management Systems (OIMS) at each of its operations worldwide that includes the aspects of EPA's prevention program and this summary describes OIMS.  Further, as already mentioned, OIMS has been attested as equivalent to ISO 14001 as a valid management system to oversee the implementation of the risk management activities. 
Additional details are included in the Data Element section of this Risk Management Plan.  Due to the ongoing nature of our safety program, the dates associated with the various activities in our accident prevention program are constantly changing.  To minimize rework, we selected May 1, 1999 as the date to begin collecting this information.  Consequently, most of the reviews / updates conducted after that date are not reflected in the Data Element information. 
Employee Participation 
The Exxon Billings Refinery enco 
urages employees to participate in all facets of process safety management and accident prevention.  Examples of employee participation range from updating and compiling operating and maintenance procedures to participating as a member of a process hazard analysis (PHA) team.  Employees have access to all information created as part of the refinery 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 refinery and addresses each accident prevention program element.  In addition, the refinery has a number of initiatives under way that 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 Exxon Billings Refiner 
y 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.  Specific groups within the refinery 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 OIMS documentation 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).  This information is supplemented by documents that specifically address known corrosion concerns and any known hazards associated with the inadvertent mixing of chemicals.  For specific process areas, the refinery has identifie 
d Operating Envelopes; i.e., documented safety-related limits for specific process parameters such as temperature, level, and compositions.  The refinery ensures that the process is maintained within these limits using computerized process controls and monitoring instruments, highly trained personnel, and protective instrument systems (e.g., automated shutdown systems, alarm systems). 
The refinery 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, electrical rating of equipment, etc.  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 
The Exxon Billings Refinery ha 
s 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 Exxon Billings Refinery primarily uses the Knowledge Based Hazard and Operability (HAZOP) study that is an adaptation by Exxon Research and Engineering and Exxon Chemical Americas of widely used industry methodologies to perform these evaluations.  HAZOP analysis is recognized as one of the most systematic and thorough hazard evaluation techniques.  The analyses are conducted using a team of people who have operating experience and engineering expertise on the process to be evaluated.  This PHA team identifies and evaluates hazards of the process as well as accident prevention and mitigation measures, and makes suggestions for additional prevention and/or mitigation measures when the team believes such measur 
es are necessary. 
The PHA team findings are forwarded to local management for resolution.  Implementation of mitigation options in response to PHA findings is based on a relative risk evaluation done by the PHA team.  This evaluation helps ensure that potential accident scenarios assigned greater risk receive attention first.  Some mitigation options, though, may involve process modifications that can only be implemented during a complete downtime of the covered process.  Implementation of such modifications therefore may extend well into the future and are subject to change.  All approved mitigation options being implemented in response to PHA team findings are tracked until they are complete.  The resolution of each finding is documented and retained. 
To ensure that the process controls and/or process hazards do not deviate significantly from the original design safety features, the Exxon Billings Refinery periodically updates and revalidates the hazard analysis results.  These per 
iodic reviews are conducted at least every 5 years for the life of the process.  The results and findings from these updates are documented and retained.  The team findings are forwarded to management for consideration, and resolution of the findings is documented and retained. 
Operating Procedures 
The Exxon Billings Refinery maintains written procedures that address various modes of process operations, such as (1) startup, (2) shutdown, (3), normal and (4) emergency operations.  These procedures can be used as a reference by experienced operators and provide a consistent basis for training of new operators.  The procedures are maintained current and accurate by revising them as necessary to reflect changes made through the management of change process.  These procedures are periodically reviewed and annually certified as current and accurate. 
In addition, the Exxon Billings Refinery maintains Operating Envelopes that provide guidance on how to respond to upper or lower limit exceed 
ances for specific process or equipment parameters.  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 safely perform their job tasks. 
To complement the written procedures for process operations, the Exxon Billings Refinery has implemented a comprehensive training program for all employees involved in operating a process.  New employees receive basic training in refinery operations if they are not already familiar with such operations.  After successfully completing this training, a new operator is paired with an experienced operator to learn process-specific duties and tasks.  After operators demonstrate (e.g., through 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 receive refresher training on the operating procedures to ensur 
e that their skills and knowledge are maintained at an acceptable level.  This refresher training is conducted at least every 3 years.  All of this training is documented for each operator, including the means used to verify that the operator understood the training. 
The Exxon Billings Refinery uses contractors to supplement its workforce during periods of increased maintenance or construction activities.  Because some contractors work on or near process equipment, the refinery 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 refinery personnel of any hazards that they find during their work.  This is accomplished by providing contractors with (1) a process overview, (2) information about safety and health hazard 
s, (3) emergency response plan requirements, and (4) safe work practices prior to their beginning work.  In addition, the Exxon Billings Refinery evaluates contractor safety programs and performance during the selection of a contractor.  Refinery personnel periodically monitor contractor performance to ensure that contractors are fulfilling their safety obligations. 
Pre-startup Safety Reviews (PSSRs) 
The Exxon Billings Refinery conducts a PSSR for any new facility or facility modification that requires a change in the process safety information and therefore, is controlled by management of change (MOC).  The purpose of the PSSR is to ensure that safety features, procedures, personnel, and the 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 systems are operationally ready.  A PSSR involves field verif 
ication of the construction and serves as a quality assurance function by requiring verification that accident prevention program requirements are properly implemented. 
Mechanical Integrity 
The Exxon Billings Refinery 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 equipment. 
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 ensur 
e that they can perform their job 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 else the equipment use will be reviewed to determine what actions are necessary to ensure the continued safe operation of the equipment. 
Another integral part of the mechanical integrity program is quality assurance.  The Exxon Billings Refinery 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 made. 
Hot Work and Other Safe Work  
The Exxon Billings Refinery has long-standing safe work practices in place to help ensure worker and process safety.  Examples of these include (1) safety orientations for visitors and contractors, (2) control of the entry/presence/exit of support personnel, (3) a lockout/tagout procedure to ensure isolation of energy sources for equipment undergoing maintenance, (4) a procedure for safe removal of hazardous materials before process piping or equipment is opened, (5) a hot work permit and procedure to control spark-producing activities, and (6) a permit and procedure to ensure that adequate precautions are in place before entry into a confined space.  These practices (and others), along with related procedures and training of affected personnel, form a system to help ensure that operations and maintenance activities are performed safely. 
Management of Change (MOC) 
The Exxon Billings Refinery has a comprehensive system to manage changes to processes.  This system requires t 
hat changes to items such as process equipment, chemicals, 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 before the change is implemented. 
Incident Investigation 
The Exxon Billings Refinery 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 of the incident or a similar incident.  The investigation team documents its findings, develops recommendations to prevent a recurrence, and forwards these results to refinery management for resolution.  Corrective actions taken in response to the investigation team's findings and recommendations are tracked until they are complete.  The 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 Exxon Billings Refinery 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.  The audit team develops findings that are forwarded to refinery management for resolution.  Corrective actions taken in response to the audit team's findings are tracked until they are complete.  The resolution of each finding is documented, and the two most recent audit reports are retained. 
The processes at the Exxon Billings Refinery have hazards that must be managed to ensure continued safe operation.  The accident prevention program summarized previously is applied to all covered processes at the Exxon Billings Refinery.  Collectively, these prevention program activities help prevent potential accident scenarios that could be caused by (1) equipment failures and (2) human errors. 
In addition to the accident prevention program activities, the Exxon Billings Refinery has safety features on many units to help (1) quickly detect a release, (2) contain / control a release and (3) reduce the consequences of (mitigate) a rele 
ase.  The following types of safety features are used in various processes: 
Release Detection 
1. Hydrocarbon detectors with alarms 
2. HF acid detectors with alarms 
3. Hydrogen sulfide (H2S) detectors with alarms 
4. TV surveillance cameras 
Release Containment/Control 
1. Process relief valves that discharge to a flare to capture and incinerate episodic releases 
2. Scrubber to neutralize chemical releases 
3. Valves to permit isolation of the process (manual or automated) 
4. Automated shutdown systems for specific process parameters (e.g., high level, high temperature) 
5. Vessel to permit partial removal of the process inventory in the event of a release (e.g., de-inventory drum) 
6. Curbing or diking to contain liquid releases 
7. Redundant equipment and instrumentation (e.g., uninterruptible power supply for process control system, backup firewater pump) 
8. Atmospheric relief devices 
Release Mitigation 
1. Fire suppression and extinguishing systems 
2. Deluge system for spec 
ific equipment 
3. Water wall mitigation system for HF acid 
4. Trained emergency response personnel 
5. Personal protective equipment (e.g., protective clothing, self-contained breathing apparatus) 
6. Blast-resistant buildings to help protect control systems and personnel 
The Exxon Billings Refinery has an excellent record of accident prevention over the life of the refinery.  There have been no accidental releases for the past 5 years that are reportable under this regulation. 
The Exxon Billings Refinery maintains a written 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 Exxon Billings Refinery 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 refinery processes or other refinery 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 Exxon Billings Refinery is coordinated with the Yellowstone County Local Emergency Pl 
anning Committee (LEPC).  This coordination includes periodic meetings of the committee, which includes local emergency response officials, local government officials, and industry representatives.  The Exxon Billings Refinery has around-the-clock communications capability with appropriate LEPC officials and emergency response organizations (e.g., Lockwood Fire District).  This provides a means of notifying the public of an incident, using the Community Alerting System if necessary, as well as facilitating quick response to an incident.  In addition to periodic LEPC meetings, the Exxon Billings Refinery conducts periodic emergency drills that involve the LEPC and emergency response organizations. 
The Operations Integrity Management Systems form the cornerstone for continuous improvement in the Exxon Billings Refinery's safety-related systems.  These systems are evergreen and are in a continuous state of improvement, usually through many small improve 
ment steps such as implementation of recommendations from hazard reviews and incident investigations.  Some specific examples of changes that are planned: 
7 Consider decreasing the process chemical inventory involving the use of HF acid in the Alkylation unit 
7 Consider the installation of a hydrocarbon release detection system in the Light Ends fractionation area 
7 Consider improving the spill control dikes in the tank farm 
7 Consider upgrading existing safety training videos 
7 Consider upgrading existing contractor selection process
Click to return to beginning