Vastar Resources, Inc. - Big Thicket Gas Plant - Executive Summary

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

Big Thicket Gas Plant Risk Management Plan 
Executive Summary 
Vastar Resources, Inc.s (Vastars) policy is to manage all operations in a manner that  
protects the environment and the health and safety of employees, customers,  
contractors, and the public. This 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. While prevention is our goal, if a release  
does occur, trained personnel will respond to control and contain the release. 
Vastars Big Thicket Gas Plant, located north of Vidor, Texas, operates a variety of  
processes to extract natural gas liquids from natural gas. The plant has hydrocarbon  
mixtures containing regulated flammable substances including methane, ethane,  
propane, n-butane, iso-butane, n-pentane, and iso-pe 
ntane. The plant does not have  
threshold quantities of any regulated toxic substances. 
Vastar became the owner and operator of the Big Thicket Gas Plant in January, 1999. 
The worst-case scenario (WCS) is failure of a 45,000-gallon storage tank containing  
natural gas liquids (NGL) resulting in a vapor cloud explosion (VCE). Based on the TNT  
equivalency method contained in EPAs RMP Offsite Consequence Analysis Guidance,  
the WCS would impact public receptors. 
The alternative release scenario (ARS) is a VCE resulting from the release of 2,900  
gallons of NGL, which is the normal inventory of the 45,000-gallon storage tank. (The  
NGL storage tanks are almost never filled to capacity.) While vapor cloud explosions  
generally are considered unlikely events, this ARS is more likely than the WCS. 
Based on flash formation factors from EPAs RMP Offsite Consequence Analysis  
Guidance and a yield factor of 0.03, this ARS would not impact any public re 
Further work on developing ARSs was not performed for the following reasons: 
? Any ARS that would impact public receptors would impact exactly the same  
receptors as the WCS.  
? The only scenario which would impact public receptors is a VCE involving an  
almost full inventory (say, 80 to 99 % full) of an NGL storage tank. This would not  
represent a significantly more practical scenario for planning purposes as opposed  
to the WCS. 
The following is a summary of the accident prevention program in place at the plant.  
Because processes at the gas plant that are regulated by the Environmental Protection  
Agency's (EPA's) risk management program (RMP) 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  
Employee Participation 
The Big Thicket Gas Plant encourages employees to participate in all facets of process  
safety management and accident 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.  
Process Safety Information 
The Big Thicket 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/co 
nfiguration information. Specific  
departments within the gas plant are assigned responsibility for maintaining up-to-date  
process safety information. Reference documents are readily available as part of the  
written employee participation plan and management is ready 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 gas plant has documented safety-related  
limits for specific process parameters (e.g., temperature, level, composition) in a Key  
Process Parameter Document. The gas plant ensures that the process is maintained  
within these limits using process controls and monitoring instruments, h 
ighly 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, 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 Big Thicket 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. 
Big Thicket Gas Plant primarily uses the hazard and operability (HAZOP) analysis  
technique 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 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 f 
indings 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 team findings are forwarded to  
management for consideration, and the final resolution of the findings is documented  
and retained. 
Operating Procedures 
The Big Thicket 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. Thes 
e 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 certified 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 Big Thicket Gas Plant maintains a Key Process Parameter Document  
that 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 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 Big Thicket Gas  
Plant has implemented a comprehensive training program for all employees involved in  
operating a process. New employees receive basic trainin 
g 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) 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 ensure 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 Big Thicket 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 work. 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 Big Thicket 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. 
Pre-startup Safety Reviews (PSSRs) 
The Big Thicket Gas Plant  conducts a PSSR for any new facility or fa 
cility 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 systems are operationally ready. The PSSR  
review team uses checklists to verify all aspects of readiness. A PSSR involves field  
verification of the construction and serves a quality assurance function by requiring  
verification that accident prevention program requirements are properly implemented. 
Mechanical Integrity 
The Big Thicket 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 progr 
am 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 bac 
k 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 Big  
Thicket 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 made. 
Safe Work Practices 
The Big Thicket Gas Plant has 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 spark-producing a 
ctivities (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 Big Thicket Gas Plant has a comprehensive system to manage changes to all  
covered processes. This system requires that 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  
changes. In addition, operating and maintenance personnel are provided any  
necessary training on the change. 
Incident Investigation 
The Big Thicket 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 inves 
tigation 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 Big  
Thicket 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 may 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  
The processes at the Big Thicket Gas Plant 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  
Universal Prevention Activities 
The accident prevention program summarized previously is applied to all RMP-covered  
processes at the Big Thicket 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 Big Thicket 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 a release.  
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  
2. Valves to permit isolation of the process (manual or automated) 
3. Automated sh 
utdown systems for specific process parameters (e.g., high  
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 
Vastar became owner and operator of the Big Thicket Gas Plant in January, 1999.  
During the five months that Vastar has operated the plant, there have been no incidents  
resulting from RMP regulated substances in covered processes that have caused  
either: (1) onsite deaths, injuries, or significant property damage, or (2) offsite deaths,  
injuries, property damage, evacuations, sheltering in place, or environmental damage.  
To Vastars knowledge, there were no such incidents for at least four yea 
rs, 7 months  
immediately prior to Vastar becoming operator. 
The Big Thicket Gas Plant maintains a written emergency response program, which is  
in place to protect both workers and the public. The program consists of procedures for  
responding to an incident, 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 necess 
ary to perform their specific emergency  
response duties. The emergency response program is updated when necessary based  
on modifications made to Big Thicket 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 Big Thicket Gas Plant  is coordinated  
with the Orange County Local Emergency Planning Committee (LEPC). The 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.  
The Big Thicket 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: 
1. Upgraded process control system to use distributed computerized control system, 
2. Hydrocarbon release detection system in the liquefied petroleum gas (LPG) loading  
rack area, 
3. Revised personnel training programs, and 
4. Revised written operating procedures in the amine treatment area.
Click to return to beginning