Little Cottonwood Water Treatment Plant - Executive Summary
Executive Summary |
Introduction and Background
The USEPA's Clean Air Act Amendments of 1990 included provisions that require facilities that use certain substances to develop a plan to reduce the likelihood of an accidental release of the substances to the atmosphere and reduce the likelihood of serious harm to the public and the environment. The plan must also include mitigation measures to reduce the potential impact on the public in the unlikely event of a release. The requirements of this plan, commonly referred to as a Risk Management Plan (RMP), are detailed and codified in 40 CFR Part 68.
The Metropolitan Water District of Salt Lake City (the District) Little Cottonwood Water Treatment Plant (LCWTP) and the Deer Creek Intake Structure (DCIS) stores chlorine in quantities above the regulatory thresholds at which a RMP/PSM is required. Chlorine is used at the LCWTP to disinfect the drinking water prior to public consumption and periodically at the DCIS to control biofouling of t
The RMP/PSM consists of three compliance programs, each with progressively stricter compliance standards. Since the District is a political subdivision of the State of Utah, State and federal OSHA regulations do not expressly apply. However, the District is required by the Utah Labor Code to operate and maintain an occupational safety and health program equivalent to the program for other employers in the state. The District generally does this by looking to OSHA regulations for guidance, subject to the District's ability to independently make decisions which best meet its safety needs. Consistent with this approach the District has chosen to use the OSHA Process Safety Management (PSM) Standards as a guide. For this reason, and the fact that a worst-case release of chlorine could affect the public, the chlorination process at LCWTP and DCIS will be treated as subject to Program 3, the most stringent of the three programs.
The RMP/PSM consists of three major parts. The f
irst part is the Hazard Assessment, which evaluates the potential effects that a release of a regulated substance could have on the public. The second part is a Prevention Program that consists of 12 elements designed to improve the system safety and decrease the likelihood of a release. The third part is the Emergency Response Program, which develops a plan for dealing with a release in the unlikely event that one would occur. Because the RMP and PSM regulations are very similar, the Prevention Program and the Emergency Response Program for the EPA RMP also serve as a substantively equivalent OSHA PSM plan.
A hazard assessment was performed to evaluate the effects that a release would have on the public. The hazard assessment includes examining the water treatment plant's 5-year accident history and hypothetical worst-case and alternative release scenario. An examination of the LCWTP and the DCIS's accident history reveals that no accidents have occurred with respe
ct to the chlorine process in the last 5 years. For the worst-case and alternative release scenarios, the distance from the point of release to the "toxic endpoint," or the location at which individuals could be exposed for up to 1 hour without experiencing serious health effects, was approximated. An estimate of the population potentially affected by a release of chlorine was also determined, along with sensitive receptors such as hospitals and schools.
The hazard assessment requires that the "toxic endpoint", or distance from the point of release to a location at which the chlorine concentration equals 3 ppm, must be determined.
The regulations require the development of a worst-case release scenario based on conservative assumptions. For a 1-ton chlorine container, which is the largest size LCWTP and DCIS handles, it is required to assume that 2,000 pounds of chlorine will be released over 10 minutes. It should be noted that this is unlikely to occur since th
e properties of chlorine would cause a freeze-and-thaw cycle to occur at the leak, which would slow the release. In addition, the worst-case scenario requires that conservative atmospheric conditions be assumed that result in a large area of impact. To model this scenario for both facilities, the EPA's computer program RMP*Comp was used. This program approximates the impact radius at which the chlorine concentration is equal to or exceeds the "toxic endpoint".
The radius is a distance of 1.3 miles from the chlorine storage area at the LCWTP. It should be noted that for the LCWTP, the urban setting was used which assumes that numerous obstacles, including buildings and trees will hinder the dispersion of chlorine.
The radius is a distance of 3.0 miles from the chlorine storage area at the DCIS. It should be noted that for the DCIS, the rural setting was used which assumes that the terrain is open, flat and unobstructed. This assumption was used to present a more cons
ervative scenario due to the confined nature of the river valley.
Because the cloud from a chlorine leak would disperse relatively quickly, an individual at a "toxic endpoint" would be exposed to the exposure limit concentration for much less than the 1 hour assumed by the limit. In addition, the exposure limit concentrations result in relatively minor health effects. Therefore, an individual at the toxic endpoint would be affected less than the results of the worst-case scenario may imply.
Alternative Release Scenario
The RMP rule also requires that at least one alternative release scenario be evaluated for chlorine. The alternative release scenario reflects a type of release that is more likely to occur compared to the worst-case scenario. The alternative release scenario selected by the District staff was a release of chlorine through a leaking fusible plug on the chlorine cylinder. Using RMP*Comp for this scenario at both facilities, the radius of impact is approximately 0.2 mil
es for LCWTP and 0.4 miles for DCIS. This alternative release scenario is considered to be more representative of the effects likely in the event of a release.
The Prevention Program, together with the Emergency Response Program, make up the RMP/PSM. The Prevention Program consists of 12 elements designed to improve the system safety and decrease the likelihood of a release.
The participation of the District staff in preparing the RMP/PSM program was critical to the program's successful implementation. Employee participation is valuable because it increases the safety awareness of the staff and it allows the staff's experience in operating and maintaining the processes to be incorporated into the plan.
District staff participated in the development of the Prevention Program by participating in the Process Hazard Analysis that is described below. The operations and maintenance staff also participated in the development of the RMP by reviewi
ng and commenting on operating and maintenance procedures and safe work practices; these personnel will continue to review and update these practices and procedures on a regular basis. All District staff received RMP/PSM awareness training that instructed staff on how the RMP/PSM requirements may impact their jobs. Staff who operate and maintain the RMP/PSM processes were trained in how to safely maintain and operate the processes.
Process Safety Information
The RMP regulations require that information concerning process chemicals, technology, and equipment be compiled as part of a RMP program. Emergency response planners can use such information to develop training programs and procedures, or as a general resource. The information will be supplied to contractors who will work in the chlorine areas as part of the requirements outlined in the Contractors element. All the required process safety information was compiled as required by the RMP regulations. The information meets and in
many cases exceeds the minimum required by the regulations.
Process Hazard Analysis
A process hazard analysis (PHA) was conducted to systematically evaluate potential causes and consequences of accidental releases. This information was used by District staff to improve safety and reduce the consequences of accidental releases. Equipment, instrumentation, utilities, human actions, and external factors that might affect the process were the focus of the PHAs that were performed for the chlorine process.
The chlorine PHA was conducted by an interdisciplinary team of District staff familiar with the process operation and maintenance and plant management. The PHA was done using a combination of "What-If" and "Checklist" methods. Based on the results of the PHAs, numerous changes in operating, maintenance, and other process safety management procedures that would improve the overall safety of the District were identified. The changes that most affect the severity and likelihood of a relea
se have been adopted by the District and incorporated as part of the overall Process Safety Management Program. The other improvements and process modifications to reduce or eliminate potential hazards are scheduled to be implemented or incorporated.
All changes resulting from the PHA are scheduled to be completed by approximately August 1, 1999. One potential change resulting from the findings of the PHA, a seismic upgrade of the facility, is currently being considered by the District. Due to the high cost, this upgrade may take years to complete. Because there are currently no definitive plans to complete this activity, it was not considered in the August 1 completion date listed below.
Operating procedures for the chlorination process have been updated as part of the RPM/PSM. Written operating procedures assure continuous, efficient, and safe operation of the facility. The goal of the operating procedures is to provide clear instructions to safely operate
the process. Operating procedures are also used to train new employees and to provide refresher training for existing staff.
The detailed operating procedures include startup, shutdown and emergency operating procedures. The procedures describe how the system should be operated in order to minimize the chances of an accidental release. The procedures also emphasize safety considerations during operation and address hazardous situations that can occur and how to correct them.
An effective RMP/PSM training program can significantly reduce the number and severity of accidental release incidences. Employees involved in operating or maintaining the chlorination process must receive training that includes applicable operating and maintenance procedures and an overview of the process. Training must emphasize safety and health hazards and safe work practices.
District staff have received initial training on the operations and maintenance of the regulated processes, an overview of
each of the RMP/PSM plan elements, and the procedures that must be followed to comply with the requirements of the RMP/PSM plan. In addition to RMP/PSM plan training, select District staff have been trained to respond to an accidental release. Refresher process operation training must be provided at least every 3 years. Refresher training for emergency response is conducted annually.
The District must make contractors aware of the known hazards of the chlorine process related to the contractors' work. In addition, the District must make contractors aware of the applicable elements of its emergency response plan. The District screens contractors for ones who can perform work on or adjacent to the chlorine process without compromising the safety and health of employees at the facility.
Before allowing a contractor to work on or adjacent to the chlorine process, the District must obtain and evaluate information regarding the contractor's safety performance and programs. Wh
en a contract involving work on or adjacent to the chlorine process is to be bid, the bidding procedures must ensure that contractor safety management requirements are met. If a contractor is to work in or adjacent to any covered processes, a safety briefing, to make the contractor aware of the District's RMP/PSM plan requirements, must be conducted before work begins. Upon arriving at the plant for the first time to perform work, the contractor will be presented a Contractor Safety Management Briefing Form that must be read and signed. All contractors should receive an Emergency Response Summary Sheet.
A pre-startup safety review must be conducted for any new covered process or for significant modifications to the existing chlorine process that necessitate a change in the process safety information. No new or significantly modified process will start up and no acutely hazardous chemicals will be introduced into such a process prior to the pre-startup safety revie
w. The purpose of the pre-startup safety review is to ensure that the facility is ready to operate new and modified regulated processes safely.
To initiate the pre-startup safety review, all updated elements of the Process Safety Management Plan are assembled for review. This includes all process safety information, process hazard analysis, operating procedures, employee training and mechanical integrity. A pre-startup safety review team completes a pre-startup checklist. The pre-startup safety review team should complete and sign a Pre-startup Safety Review Form. This form documents the process, and helps ensure that the review has been properly performed. The Pre-startup Safety Review Form must be authorized before startup.
An effective mechanical integrity program is one of the primary lines of defense against a release. The mechanical integrity program also addresses equipment testing and inspection, preventative maintenance schedules, and personnel trainin
g. The intent is to ensure that equipment used to process, store, or handle chlorine is maintained and installed to minimize the risk of releases.
The District maintenance staff use a computerized maintenance management system, referred to as the Preventative Maintenance (PMC) to store equipment information, generate and prioritize work orders, schedule preventative maintenance, provide safety procedures for work orders, and maintain an inventory of parts and materials. The PMC system is used to generate work orders for preventative maintenance. In addition to preventative maintenance, the District staff performs corrective maintenance in the event of equipment malfunction or breakdown. Work orders indicate what safety precautions must be followed including whether lockout/tagout or confined space entry provisions are applicable. The staff that carryout maintenance are all trained as part of the RMP/PSM.
Hot Works Permits
RMP/PSM regulations require employees and contractors to empl
oy safe work practices when performing "hot work" in, on, or around the chlorine process. To ensure that hot work is done safely, a Hot Work Permit Program has been developed that requires a permit to be issued before hot work is performed. Hot work is defined as the use of oxyacetylene torches, welding equipment, grinders, cutting, brazing, or similar flame- or spark-producing operations.
The process of completing the hot work permit makes it necessary to identify the hazard, recognize what safeguards are appropriate, and then initiate the safeguards necessary to ensure a fire-safe workplace. Following the standards outlined in this section of the RMP aid in complying with the OSHA Hot Works Regulations (1910.252(a)).
Management of Change
A system for the proper management of changes and modifications to equipment, procedures, chemicals, and processing conditions is required under the RMP/PSM. Modifications to the chlorine process will be reviewed before they are implemented to eva
luate if the modification would compromise system safety. An effective change management system will help minimize the chance for an accidental release.
If a modification covered under RMP/PSM is made, its effects must be addressed, employees must be informed, and the written procedures must be updated. The intent is to require that all modifications to equipment, procedures, and processing conditions other than "replacement in kind" be managed by identifying and reviewing them before implementation. A Management of Change Committee will evaluate any modifications that are covered under the RMP/PSM. The Management of Change Committee will complete a Management of Change Form that the Water Quality Manager will review and authorize prior to initiation of a covered change.
Each incident that resulted in or could reasonably have resulted in a catastrophic release of chlorine must be investigated. A process to identify the underlying causes of incidents and to imp
lement procedures for preventing similar events has been developed. To investigate an incident, an investigation team will be established. As part of the investigation, an incident report will be prepared to recommend system changes.
The investigation team should ask questions such as what equipment failed, which behavior failed, and which material leaked, reacted, or exploded? As part of the incident review, staff actions that may have contributed to the incident will also be reviewed. A determination will be made as to whether it is necessary to institute additional training for the employees to prevent the incident from occurring in the future. On the incident report form, the Water Quality Manager identifies which of the recommended system changes are approved for implementation. The incident investigation report and any changes resulting from the report will be reviewed with all staff members who operate and maintain the applicable system.
The District is requ
ired to complete a compliance audit for the RMP/PSM program. The primary goals of conducting an internal compliance audit are to gather sufficient data to verify compliance with RMP/PSM requirements and good process safety practices, identify process safety deficiencies and develop corrective actions, and increase safety awareness among District staff.
The compliance audit methodology is modeled after OSHA's guidelines for conducting regulatory PSM compliance audits: Compliance Guidelines and Enforcement Procedures, OSHA Instruction CPL 2-2.45A CH-1 (September 13, 1994). An internal compliance audit must be conducted at the plant at least once every 3 years for the chlorine process. A team that includes at least one person knowledgeable in the covered processes and an audit leader knowledgeable in RMP/PSM requirements and audit techniques will conduct the audits. The Water Quality Manager and the audit team will promptly determine an appropriate corrective action for each deficiency i
dentified during the audit and document the corrective actions and the dates by which they must be taken.
Emergency Response Program
The Emergency Response Program documents a plan for dealing with a release. OSHA Process Safety Management regulation 29 CFR 1910.119(n) and EPA RMP regulation 40 CFR 68 Subpart E require that an Accidental Release Emergency Response Plan be prepared. The plan must be prepared in accordance with the provisions of another overlapping OSHA regulation-Employee Emergency Plans (29 CFR 1910.38(a)). In addition, provisions of the OSHA hazardous waste and emergency response standard, 29 CFR 1910.120 (q), must also be considered. The Emergency Planning and Response Plan described in this section of the RMP complies with the requirements of 40 CFR 68.95, 29 CFR 1910.38(a), and 29 CFR 1910.120(q).
The Emergency Planning and Response plan , "Metropolitan Water District of Salt Lake City Facility Emergency Response Plan", provides specific emergency response proc
edures for accidental release of chlorine. The emergency response procedures cover a release from the initial alarm stage through either leak stoppage or HAZMAT assistance. As part of the emergency response procedures there are plans for victim rescue, leak investigation, and communication with additional support agencies. In addition, critical plant operations are identified to insure that, if possible, the critical District functions are kept operational. The Emergency Planning and Response plan also indicates the level of training needed to carryout the emergency response procedures. Only personnel trained at the Hazardous Materials Technician Level can attempt to stop a leak. The emergency response procedures also covers situations where plant evacuation is necessary.
Information regarding self contained breathing apparatus is also provided in the Emergency Planning and Response plan. It also addresses plant site communication, emergency response equipment, first aid and medical t
reatment, medical surveillance and consultation, and emergency response drills.