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Cox City Processing Plant

Parent Companies:
Enable Midstream Partners
EPA Facility ID:
Other ID:
Facility DUNS:
Parent Company DUNS:


9 miles E. & 2 miles N. of Rush Spr
Rush Springs, OK 73082
Lat / Long:
34.796, -97.801 (Get map)
Interpolation - Photo
Center of Facility
Horizonal accuracy:
25 m
Horizontal reference datum:
North American Datum of 1983
Source map scale:


Enable Midstream Partners
(405) 525-7788
One Leadership Square, Suite 1000
North Tower, 211 N Robinson
Oklahoma City, OK 73102
Foreign Address:

Person responsible for RMP implementation:

Paul Brewer
Executive Vice President,Operations

Emergency contact:

Kervin Schulz
O&M Leader
(580) 476-3364
24-hour phone:
(800) 522-8048
Ext or PIN:

Other contacts:

Facility (or company) email:
Facility phone:
Facility (or company) URL:


Local Emergency Planning Committee:
Grady County LEPC
Full-Time Equivalent Employees:
Covered by OSHA PSM:
EPCRA section 302:
CAA Title Air Operating Permit:
CAA Permit ID#:
OSHA Star/Merit Ranking
Last Safety Inspection Date:
April 4, 2016
Inspecting Agency:
Using Predictive Filing:


Cox City Processing Plant
CBI claimed:
Program Level:
Natural Gas Liquid Extraction (211112)
Chemical name
Quantity (lbs.)
Flammable Mixture
Public OCA Chemical

RMP Preparer:

Stephen Swanson
One Leadership Square, Suite 1000
North Tower, 211 N Robinson
Oklahoma City, OK 73102
Foreign Address:

(405) 530-7478

Latest RMP Submission:

May 6, 2016
Voluntary update (not described by any of the above reasons)


Effective Date:
Other Reason:

2. Toxics: Worst-case


3. Toxics: Alternative release


4. Flammables: Worst-case

Some Risk Management Plan information is not provided in the available RMP data. You need to make an appointment at an EPA Reading Room In order to get access to details from the Off-Site Consequence Analysis (OCA) such as:

Instructions on how to make an EPA appointment can be found here.

Public OCA Chemical (in Cox City Processing Plant)
CBI claimed:
Model used:
EPA's OCA Guidance Reference Tables or Equations
Passive mitigation
  • None
not considered:
  • Blast walls

5. Flammables: Alternative release

Some Risk Management Plan information is not provided in the available RMP data. You need to make an appointment at an EPA Reading Room In order to get access to details from the Off-Site Consequence Analysis (OCA) such as:

Instructions on how to make an EPA appointment can be found here.

Public OCA Chemical (in Cox City Processing Plant)
CBI claimed:
Model used:
EPA's OCA Guidance Reference Tables or Equations
Passive mitigation
  • None
not considered:
  • Dikes
  • Fire wall
  • Blast walls
  • Enclosures
Active mitigation
  • None
not considered:
  • Sprinkler systems
  • Deluge systems
  • Water curtain
  • Excess flow valve

6. Five-year accident history

Dec. 8, 2010 at 11:15
Natural Gas Liquid Extraction (211112)
30 hours
Chemicals involved:
  • Flammable Mixture
Release events:
Weather conditions at time of event
Wind speed:
None ℉
Atmospheric stability:
Precipitation present:
Unknown weather conditions:
On-site impacts
Deaths of employees or contractors:
Deaths of public responders:
Deaths of public:
Injuries of employees or contractors:
Injuries of public responders:
Injuries of public:
Property damage:
Known off-site impacts
Medicals treatments:
Property damage:
Environmental damage:
  • None
Initiating event:
Equipment Failure
Contributing factors:
  • None
Off-site responders notified:
No, not notified
Changes introduced as a result of the accident:
  • Improved/upgraded equipment

7. Prevention: Program level 3

Cox City Processing Plant, Natural Gas Liquid Extraction (211112)
Prevention Program ID:
Safety Review Date
March 1, 2016, since latest RMP submission
PHA Update Date
Nov. 11, 2014, since latest RMP submission
PHA Techniques
  • Checklist
Hazards Identified
  • Fire
  • Explosion
  • Overpressurization
  • Corrosion
  • Overfilling
  • Contamination
  • Equipment failure
  • Cooling loss
  • Tornado
Process Controls
  • None
Mitigation Systems
  • Dikes
  • Enclosure
Monitoring Systems
  • None
Changes since PHA
  • None
Training Type
  • Classrom
  • On the Job
Competency Testing
  • None
Procedure Review Date
April 12, 2015, since latest RMP submission
Training Review Date
March 1, 2016, since latest RMP submission
Maintenance Review Date
July 5, 2013, since latest RMP submission
Maintenance Inspection Date
Dec. 3, 2015, since latest RMP submission
Equipment Tested
Management of Change Most Recent Date
April 28, 2016
Management of Change Review Date
March 1, 2016
Pre-startup Review Date
Jan. 13, 2016
Compliance Audit Date
Oct. 2, 2013
Compliance Audit Change Completion Date
Oct. 2, 2014
Incident Investigation Date
May 16, 2014
Incident Invest. Change Completion Date
May 16, 2015
Participation Plan Review Date
March 1, 2016
Hot Work Review Date
March 1, 2016
Contractor Safety Review Date
March 1, 2016, since latest RMP submission
Contractor Safety Eval. Date
April 16, 2014, since latest RMP submission

8. Prevention Program level 2

No Prevention Program level 2

9. Emergency response

Facility In Community Plan:
Facility Own Response Plan:
Specific Facility Response Plan:
Inform. Procedures in Response Plan:
Emergency Care in Response Plan:
Plan Review Date:
Response Training Date:
Feb. 18, 2016
Local Response Agency:
Local Response Agency Phone:
(405) 222-2339
Subject To - OSHA EAP:
Subject To - CWA:
Subject To - RCRA:
Subject To - OPA:
Subject To - State EPCRA:
Subject To - Other:

Executive Summary

Enable Midstream Cox City Natural Gas Processing Plant

Executive Summary


Enable Midstream and the Cox City Natural Gas Processing Plant have a long-standing commitment to worker and public safety. Our commitment is demonstrated by the capital and human resources invested in our accident and accidental release prevention / mitigation programs. Enable Midstream's mitigation efforts include; personnel training, safety engineered design; thorough process hazard analyses; compliance audits; management of change; contractor oversight; and planned equipment installation / operation / maintenance of our processes. Enable Midstream's policy is to implement reasonable controls to prevent foreseeable releases of regulated substances. However, if a release does occur, gas plant personnel are trained to follow Enable Midstream's emergency response operating procedures in an effort to safely avert further release and minimize the impact to public and environmental receptors.


The Cox City Natural Gas Processing Plant, located approximately 9 miles east and 2 miles north of Rush Springs in Grady County, Oklahoma, operates a cryogenic expander plant with refrigeration assist to extract liquid petroleum products from raw natural gas. Plant regulated substances held above threshold quantities include pipeline quality natural gas (primarily methane), condensate and natural gas liquids (NGL) both comprised primarily of ethane, propane, butane, pentane, and heavier hydrocarbons. The plant also utilizes HD-5 Propane for refrigeration(approx. 96% propane with small amounts of ethane and butanes), held in the process in excess of the threshold quantity.

In addition to following the Environmental Protection Agency's (EPA) Risk Management Program (RMP), the Cox City Plant follows applicable laws set forth in Occupational Safety and
Health Administration's (OSHA's) Process Safety Management (PSM) standard 29 CFR 1910.119.


Under the RMP regulations, the Cox City Natural Gas Processing Plant is classified as a Program Level 3 facility. Under Program Level 3 guidelines, the Worst-Case Scenario (WCS) associated with a release of a regulated flammable substance is a Vapor Cloud Explosion (VCE) involving the full inventory of the largest storage tank containing the C1+ mixture. A written procedure is in place to limit the storage inventory to 365,684 pounds (80% of the maximum tank capacity). However, for Worst Case Scenario calculations, the full inventory (100% maximum tank capacity of 457,105 pounds) of this tank is assumed to release and ignite, resulting in a VCE. The maximum distance to the 1-psi overpressure endpoint for this WCS is 0.62 miles (3,265 feet). Additionally, 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 the WCS for the Cox City Natural Gas Processing Plant.

The Alternative Release Scenario (ARS) for flammable substances at the Cox City gas plant is a VCE resulting from a release of 8,325 pounds of C1+ mixture over a sixty (60) minute period, resulting from a seal failure at the stabilizer feed pumps. The hypothetical release is expected to be isolated by an operator in less than sixty minutes (active mitigation). The maximum distance to the 1-psi overpressure endpoint for this event is 0.16 miles or 859 feet. This event was selected as being a practical scenario for use in emergency planning and response.


The following is a summary of the accidental release prevention program in place at the Cox City Natural Gas Processing Plant. Because the processes at the gas plant which are regulated by the EPA's RMP rule are also subject to the OSHA's PSM re
gulation, this summary addresses each of the OSHA PSM elements and describes the management system in place to implement the accidental release prevention program.

Employee Participation

The Cox City Natural Gas Processing 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. In addition, the gas plant 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. Operations personnel also participate in the development and review of operating procedures, Process Safety Information (PSA), and training and mentoring of other personnel.

Process Safety Information

The Cox City Natural Gas Processing Plant develops and maintains 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 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 emp
loyee 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). 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 our Operating Procedures and/or Process Safety Information. 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, 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 Cox City Natural Gas Processing 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 Cox City Natural Gas Processing 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 Enable Midstream personnel and/or contractors who have operating and maintenance experience as well as engineering expertise. This PHA 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's recommendations are reviewed with corporate management to approve or revise recommended mitigation actions. Once approved, mitigation actions are assigned a relative risk ranking based upon the magnitude / immediacy of necessary actions to reduce hazard risks - as deemed necessary by the PHA Team, PHA Team Leader, and/or Corporate Management. This risk reduction ranking helps ensure that potential accident scenarios assigned the highest risk receive immediate attention. All management-approved PHA Team recommendations are tracked until they are completed. The final resolution of each finding is documented and retained.

Periodically, the Cox City Natural Gas Processing Plant updates and revalidates the initial PHA to ensure that process controls remain technologically adequate, and that process hazards are minimized and are within acceptable company risk tolerances. The PHA Revalidation verifies that the process does not deviate significantly from its original engineering design and safety features. These periodic revalidations / reviews are conducted at least every 5 years and will be conducted at this frequency until the process is decommissioned. As with the initial analysis, the PHA Team findings / recommendations will be forwarded to corporate management for approval / revision and the final resolution of the action tasks will be documented and retained.

Operating Procedures

The Cox City Natural Gas Operating Plant maintains written procedures that address various modes
of process operations, including (1) initial startup, (2) normal operations, (3) temporary operations, (4) emergency shutdown, (5) normal shutdown, and (6) startup following a turnaround or after an emergency shutdown. 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 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 Cox City Natural Gas Processing Plant maintains Operating Procedures and/or process safety information that provide guidance on how to respond to upper or lower limit exceedances for specific process or equipment parameters. This information 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 Cox City Natural Gas Processing 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 and 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 training is documented for each operator, including the means used to verify that the operator understoo
d the training.


The Cox City Natural Gas Processing Plant uses contractors to supplement its work force 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 Cox City Natural Gas Processing 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 Cox City Natural Gas Processing Plant conducts a Pre-Startup Safety Review (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 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 im

Mechanical Integrity

The Cox City Natural Gas Processing 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 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 Cox City Natural Gas Processing 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 Cox City Natural Gas Processing Plant has long-standing safe work practices in place to help ensure worker and pr
ocess 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 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 (MOC)

The Cox City Natural Gas Processing 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 these changes. In addition, operating and maintenance personnel are provided any necessary training on the change.

Incident Investigation

The Cox City Natural Gas Processing 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 of the incident or a similar incident. The investigation team documents its findings, develops recommendations to p
revent 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 accidental release prevention program is functioning properly, the Cox City Natural Gas Processing Plant periodically conducts an audit to determine whether the procedures and practices required by the accident prevention program are being implemented. Compliance audits are required at least every 3 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.


The processes at the Cox City Natural Gas Processing 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 facility.

Universal Prevention Activities

The accident prevention program summarized previously is applied to all processes at the Cox City Natural Gas Processing 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 Cox City Natural Gas Proces
sing 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 release. The following types of safety features are used in the covered processes:

Release Detection

? Hydrocarbon area detectors with alarms and shutdowns.

? High/Low process alarms and shutdowns.

? Plant is staffed 24-hours a day, 7-days a week.

Release Containment/Control

? Pressure relief valves that discharge into a flare system, which will capture and incinerate episodic releases

? Valves to permit isolation of the process (manual or automated)

? Automated shutdown systems for specific process parameters (e.g., high temperature)

? Curbing or diking to contain liquid releases

? Redundant equipment and instrumentation (e.g., uninterruptable power supply for process control system)

? Atmospheric pressure relief devices

Release Mitigation

? Fire extinguishers

? Personnel trained in company emergency response procedures

? Personal protective equipment (e.g., chemical protective clothing)


The Cox City Natural Gas Processing Plant has an excellent record of accidental release prevention over the past 5 years. There have been no accidental releases that have occurred in the past 5 years that have resulted in offsite effects. Every incident is investigated thoroughly to determine ways to prevent similar incidents from recurring. The following table is a summary of the number of RMP incidents that have occurred during the past 5 years.

2012 2013 2014 2015 2016

Number of RMP Events with Onsite Effects 0 0 0 0 0

Number of RMP Events with Offsite Effects 0 0 0 0 0


The Cox City Natural Gas Processing Plant maintains a written emergency response program, which is in place to protect worker and public safety as well as the e
nvironment. The program consists of procedures for responding to a release of a regulated substance, including the possibility of 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. Company personnel are also available to assess post-incident cleanup and decontamination requirements. In addition, the plant has procedures that address maintenance, inspection, and testing and 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 lessons learned from other Enable Midstream gas plant facilities.

The overall emergency response program for the Cox City Natural Gas Processing Plant is coordinated with the Grady County Local Emergency Planning Committee (LEPC) and the local fire department. This coordination includes periodic meetings of the LEPC, which includes local emergency response officials, local government officials, and industry representatives. The Cox City 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.


The Cox City Natural Gas Processing Plant places high priority in resolving findings and recommendations from PHAs, safety audits, and incident investigations, some of which may result in modifications to the process and procedures. The following changes have been completed in respon
se to these types of activities:

? Revisions / enhancements to personnel training programs

? Revisions / enhancements to contractor safety programs

? Revisions / enhancements to mechanical integrity programs

? Revisions / enhancements to site security and access control