City of Lawton Water Treatment Plant - Executive Summary

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ES.1     INTRODUCTION 
 
The Lawton Water Treatment Plant (WTP) located  in Medicine Park, Oklahoma, uses chlorine gas as a disinfectant. The concentrated form of this disinfection agent, before it is mixed with water, can be extremely hazardous if a sudden release of the vessel contents occurs. Chlorine gas is carefully stored and handled to prevent its accidental release. This Risk Management Plan (RMP) describes the chemical hazards of chlorine gas and explains what the Lawton WTP is doing to prevent an accidental release. This plan has been developed and implemented in accordance with the U.S. Environmental Protection Agency EPA) Accidental Release Prevention Provisions regulations (40 CFR 68) and guidelines. 
 
The Lawton WTP currently has a stationary source subject to EPA RMP regulations. The WTP chlorine  feeder room  consists of chlorinators that introduces chlorine gas into process water for disinfection. The chlorine feeder room is equipped with a ventilation system that, under  
normal operations, is on standby. A chlorine detector monitors the air within the room for chlorine gas. In the event that the concentration of chlorine gas exceeds 1 part per million (ppm) the leak detector alarm is sounded. 
 
The Chlorine Cylinder Storage Building  is used to store up to thirteen 1-ton chlorine cylinders. This storage building is for cylinders, which are used for disinfection on an as-needed basis. The cylinders are stored under a sheet-metal roof to protect the cylinders from the elements. They are placed on trunnions in a horizontal position on a concrete pad. 
 
The following regulated substance  at the Lawton WTP is stored in quantities above the applicable EPA RMP threshold quantity: 
 
Lawton Water Treatment Plant                    Chlorine             7782-50-5                        26,000 
 
 
The following is a brief description of the contents of the Executive Summary: 
 
* Accidental release prevention and emergency response policies. 
* Worst-case and alternative 
case release scenanios and potentially affected areas. 
* Five-year accident history. 
* Accidental release prevention program summary and chemical-specific prevention steps. 
* Emergency response program. 
* Planned changes to improve safety. 
 
ES.2    ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES 
 
The Lawton WTP is committed to protecting installation personnel, the public, and the environment from any workplace and accidental release hazards.The Lawton WTP outlines the appropriate responses to releases of hazardous chemicals in the Emergency Preparedness Plan and the Hazardous Material Incident Response Standard Operating Procedures. Safety, environmental protection, and risk management programs are fully implemented and coordinated with community emergency responders for emergency planning and response efforts. 
 
ES.3     WORST-CASE RELEASE SCENARIO 
 
Dispersion modeling was performed to estimate areas that could be affected by a worst-case release scenario under the leas 
t favorable weather conditions. Prevention and control measures were not considered in evaluating the worst-case release scenario. 
 
EPA established the release rate for the worst-case release scenario as the greatest quantity held in a single vessel or pipe divided by a 10-minute release duration. At the Lawton WTP, the worst-case scenario would consist of an accidental release of the contents of a 1-ton cylinder of chlorine gas at the WTP. The entire contents were assumed to be released at a rate of 200 pounds per minute. A major release of this magnitude is extremely rare because of the robust design of 1-ton containers and the rigorous maintenance and prevention programs. Potential causes could include faulty container construction, fall from a crane, severe corrosion. In a severe accident, it was assumed that the enclosure (Chlorine Storage Building) could potentially fail as a result of pressure buildup. Using RMP Comp software, the worst-case downwind distance to the EPA endpoint 
concentration was 3.5 miles. 
 
This worst-case scenario represents the maximum conceivable impact for a release.  Release reporting databases, and industry experience suggest that the worst-case release scenario is so unlikely that it should not be the basis for emergency planning. 
 
 
ES.4     ALTERNATIVE RELEASE SCENARIOS 
 
Dispersion modeling was also performed to estimate the affected areas for at least one alternative release scenario for each regulated substance in a regulated process. Alternative release scenarios for the WTP were evaluated.  The alternative release scenario for the WTP plant is based on a split or the decoupling of a 0.375-inch connector between the cylinder and header, resulting in the release of 317 pounds of chlorine gas over a 60-minute period. If the building is assumed to fail (as a result of buildup of internal pressure), the distance to the toxic endpoint (plume distance) was estimated to be approximately 0.6 miles (988 yards) downwind of the WTP. If the p 
lume dispersion is mitigated by the building, the plume distance is estimated to be approximately 725 yards. Based on the lower release rate for this alternative release scenario, the building is likely to successflilly mitigate the release. 
 
The most effective reduction in any risk to the community is achieved by focusing emergency planning on responding to the alternative release scenarios. 
 
ES.5     FIVE-YEAR ACCIDENT HISTORY 
 
Under the RMP regulations, an accidental release is defined as a release of a regulated substance that "resulted in deaths, injuries, or significant property damage on-site, or known off-site deaths, injuries, evacuations, sheltering in place, property damage, or environmental damage." Within the past 5 years, the Lawton WTP has had an accidental release that met the EPA RMP Rules definition of an accidental release. 
 
ES.6     PREVENTION PROGRAM 
 
Under the EPA RMP regulations, three levels of prevention program requirements have been established to match the l 
evel of effort to the risk of off-site impact. Based on the results of the worst-case release scenario consequence analysis, the 5-year accident history, the Lawton WTP must meet RMP Program 2  The Prevention Program is summarized below. 
 
Management System - A management program has been developed that assigns overall responsibility for the development and implementation of the RMProgram to a qualified individual or position of responsibility.  It clearly delineates accountability and responsibilities for any elements where responsibilities are delegated in an organization chart or table. 
 
Process Safety Informiation - Up-to-date process  safety  information  is maintained for use by employees operating the regulated process in accordance with 40 CFR 68.65, including the following: 
 
-     MSDSs for chlorine with toxicity information, permissible exposure limits (PELs), physical data,              reactivity data, corrosivity data, thermal and chemical stability data, and synergistic ef 
fects from mixing process flows. 
 
-      Block flow diagram or a simplified process flow diagram of the regulated process. 
 
-      Process chemistry, maximum intended inventory of the regulated process. 
 
-      Consequences of process deviations (from the process hazards review). 
 
-      Regulated process equipment information consisting of materials of construction, piping and  instrumentation diagrams ( P&IDs), electrical classification, relief system design and design, basic ventilation system design, design codes and standards employed, and safety systems. 
 
Process safety information was compiled prior to completing any process hazard review (PHR) for the regulated process with the exception of consequences of process deviations.  The regulated equipment complies with recognized and generally accepted good engineering practices and is designed, maintained, inspected, tested, and operated in a safe manner. 
 
Hazard Reviews -  (HR)  have been performed for all Program 2-regulated proc 
esses at the facility in accordance with 40 CtR 68.67. The HR was performed using an EPA RMP-listed methodology (What-If Checklist). The HR identified the hazards associated with the regulated substances and process; causes of potential accidental release scenarios; safeguards used to prevent accidental releases; and methods used to detect, monitor, or control accidental releases. Any issues identified during the HR were documented and resolved in a timely manner. The HR will be revalidated and updated once every 5 years following completion of the initial HR. 
 
Operating Procedures - Detailed and up-to-date process operating procedures (OPs) have been developed and are maintained for each regulated process in accordance with 40 CFR 68.69.  OPs provide clear instructions for safely conducting activities involving a regulated process in a manner consistent with process safety information and are readily available to employees involved in a regulated  process. OPs are reviewed as frequent 
ly as necessary to ensure that they remain up-to-date and are certified annually as current and accurate. 
 
OPs cover each operating phase of the regulated process, including initial system startup, normal operations, temporary operations, emergency shutdown and conditions when required, emergency operations, normal shutdown, and startup following a turnaround or emergency shutdown. OPs also incorporate relevant process safety information, including the following: 
 
Process operating limits (consequences of deviations, steps to correct or avoid deviations). 
 
Safety and health considerations (properties and hazards of chlorine, precautions necessary to prevent exposure, control measures to be taken upon physical contact or airborne exposure, quality control for control of regulated substance inventories). 
 
Safety systems and their functions. 
 
Training -  New employees working with a regulated process receive initial training in accordance with 40 CFR 68.71. The training includes an overvi 
ew of the regulated process and emphasizes process OPs, safe work practices, health and safety hazards, and emergency operations including shutdown. Those employees already involved in' operating or maintaining a regulated process prior to 21 June 1999 have been certified in writing as having "the required knowledge, skills, and abilities to safely carry out the duties and responsibilities as specified in the operating procedures." 
 
Refresher training is provided at a minimum of every 3 years to all employees involved in working with a regulated process. Documentation is maintained for each employee to ensure that he or she has received and understood the required training. 
 
Maintenance - A maintenance program has been developed in accordance with 40 CFR 68.73 for regulated process equipment. Employees involved in the maintenance of regulated processes receive additional training, which includes an overview of the process, its hazards, and applicable procedures to ensure that the emplo 
yee can perform the job in a safe manner. 
 
Written procedures have been developed to ensure that regulated process equipment is properly maintained, tested, and inspected at regular, scheduled intervals and that such  activities are thoroughly documented.  Maintenance, inspection, and testing procedures and frequencies are consistent with applicable manufacturer's recommendations and follow accepted enginering practices. Any equipment deficiencies identified during maintenance,  inspection, or testing are corrected in a safe and timely manner.  
 
Compliance Safety Audit - RMProgram compliance is confirmed through safety audits that are performed at least once every 3 years in accordance with 40 CElL 68.79. The audits are completed by at least one person knowledgeable in the process. A report of the findings is generated following the audit, and all deficiencies and or recommendations are promptly addressed and the resolution is documented. The two most recent safety audit reports are ma 
intained at the facility. 
 
Incident  Investigation - Specific  incident  investigation,  reporting,  and documentation procedures have been implemented and are followed in accordance with 40 CElL 68.81 in response to any incident involving a regulated process that did or could have reasonably resulted in a catastrophic release of a regulated substance.  Under EPA RMP, a catastrophic release is defined as a major uncontrolled emission, fire, or explosion involving one or more regulated substances that presents imminent and substantial endangerment to public health and the environment. 
 
The incident investigation procedure is initiated as soon as possible and no later than 48 hours following any incident. A team is established to perform the incident investigation and always includes at least one person knowledgeable in the process, a. contract employee if the incident involves work by a contractor, and other persons with appropriate qualifications to investigate an accident. 
 
Following  
the investigation, a written report is prepared summarizing the following information at a minimum: date of the incident; date the investigation began; description of the incident and any contributing factors; and any recommendations resulting from the investigation. When completed, the report is reviewed by all affected personnel (i.e., those that operate or maintain the process including contract employees. Incident investigation reports are maintained at the facility for a minimum of 5 years. 
 
-     Training in the work practices necessary to safely complete their work and documentation that each contract employee has received and understood the training. 
 
-     Information of known potential fire, explosion, or toxic release hazards related to their work and applicable provisions of the emergency response plan. 
 
The Lawton Water Treatment Plant is a Program 2 process, and the Lawton WTP has implemented the Prevention Program Elements described above. 
 
ES.7    EMERGENCY RESPONSE PRO 
GRAM 
 
The Lawton WTP has an emergency response program that includes an emergency response plan addressing all EPA ItNIP-regulated substances managed at the facility.  The emergency response plan contains the following: 
 
* Procedures for informing the Comanche County Civil Defense, Lawton City Manager, the Lawton Fire        Department and the surrounding communities about accidental releases. 
 
* Proper first-aid and emergency medical treatment necessary to treat accidental exposures. 
 
* Specific procedures for emergency response to either stop the release and/or evacuate people who   could be affected. 
 
* The Emergency Response Program includes the necessary emergency response equipment, personnel, and training to respond to potential releases. Procedures for emergency equipment use, inspection, testing, and maintenance have been created. 
 
In addition, The Lawton WTP's Emergency Response Plan has been coordinated with the Local Emergency Planning Committee (LEPC), Comanche County Civi 
l Defense and the Lawton Fire Department. 
 
ES.8    PLANNED OR IMPLEMENTED CHANGES TO IMPROVE SAFETY 
 
In the effort to improve safety and to reduce the risk of accidental release, changes to the RMProgram and the facility have been implemented or are currently planned. These improvements were identified either as risk reduction measures during the hazard review for the WTP chlorine system or as a result of an improved RMProgram and the dedication to an inherently safer process. 
 
The following changes are presently planned to improve process safety at the Lawton WTP: 
 
Change(s) 
 
* Formalized the RMProgram in accordance with the EPA RMP Rules. 
* Increased training for emergency response. 
* Improved maintenance, inspection, and testing program. 
* Provide training for operation of RMP-covered chlorine processes. 
* Develop emergency response procedures specific to chlorine release. 
* Incorporate RMProgram elements into regular compliance audits.
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