Joseph B. Blake Water Treatment Plant - Executive Summary
Executive Summary |
1.0 Introduction and Background
The U.S. Environmental Protection Agency's (EPA) Clean Air Act (CAA) 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 Code of Federal Regulations (CFR) Part 68.
The Joseph B. Blake Water Treatment Plant (WTP) stores chlorine in quantities above the regulatory thresholds at which an RMP is required. Chlorine is used at WTP primarily to disinfect the drinking water prior to distribution. The WTP also stores ammonia, but maximum inventory is well under RMP threshold quantity. T
hus, the ammonia process is not regulated under RMP rule.
The RMP consists of three compliance programs, each with progressively stricter compliance standards. The chlorination process at the WTP is subject to Program 2, the second most stringent of the three programs, because the worst-case modeling includes public receptors within the impact area. The process however, is not included in the specified standard industrial classification (SIC) codes and is not currently regulated under federal or state Process Safety Management (PSM) Requirements.
Program 2 of the RMP consists of three major parts. The first part is the hazard assessment. The hazard assessment is performed to determine the effects of a release of a regulated substance could have on the public. The second part is a prevention program that consists of seven 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.
2.0 Hazard Assessment
A hazard assessment was performed to determine the effects that a release would have on the public. The hazard assessment includes examining the WTP's 5-year accident history and hypothetical worst-case and alternative release scenarios. An examination of the WTP's accident history reveals that no accidents have occurred with respect 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 determined. An estimate of the population affected by a release of chlorine was also determined, along with sensitive receptors such as hospitals, schools, and nursing homes.
2.1 Worst-Case Scenario
The hazard assessment requires that the "toxic endpoint" or distance from the point of
release to a location at which the chemical concentration equals a concentration of 3 ppm for chlorine must be determined. To model this scenario, the EPA's computer program RMP*Comp was used. This program determines the impact radius at which the chlorine concentration is equal to or exceeds the "toxic endpoint". This radius is a distance of 1.3 miles from the chlorine storage area at the WTP.
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 WTP 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 the properties of chlorine would cause a freeze-and-thaw cycle to occur at the leak, which would slow the release. The worst-case scenario also requires that conservative atmospheric conditions be assumed that result in a large area of impact.
Because the cloud from a chlor
ine 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.
2.2 Alternative Release Scenario
The RMP rule also requires that at least one alternative release scenario be evaluated for chlorine. The alternative release scenario selected by the WTP staff was a release of chlorine through a broken valve during unloading. Using RMP*Comp for this scenario, the radius distance is less than 0.1 mile. This alternative release scenario is considered to be more representative of the effects likely in the event of a release and the meteorological conditions are less conservative than those that must be assumed for the worst-case scenario.
3.0 Prevention Prog
The prevention program, together with the emergency response program, make up the RMP. The prevention program consists of seven elements designed to improve the system safety and decrease the likelihood of a release.
3.1 Safety Information
The RMP regulations require that information concerning process chemicals, technology, and equipment be compiled as part of an RMP program. Emergency response planners can use such information to develop training programs and procedures, or as a general resource. If needed, the information can be supplied to contractors who will work in the chlorine process area. All of 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.
3.2 Hazard Review
A process hazard analysis (PHA) was conducted on February 23, 1999, to evaluate potential causes and consequences of accidental releases. This information was used by WTP staff to im
prove 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 processes.
The chlorine PHA was conducted by an interdisciplinary team of WTP staff familiar with the process operation and maintenance and facility management along with CH2M HILL engineers. The PHA was performed using a combination of "What If" and "Checklist" methods. Based on the results of the PHAs, some changes in operating, maintenance, and other process safety management procedures that would improve the overall safety of the WTP were identified. These have all been addressed and are being implemented.
3.3 Operating Procedures
Operating procedures for the chlorination process were developed prior to the RMP. 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 start-up, shutdown, and emergency operating procedures. The procedures describe how the system should be operated 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 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.
WTP staff have received initial training on the safety information and operations and
maintenance of chlorine. In addition to the initial training, select WTP 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.
An effective maintenance program is one of the primary lines of defense against a release. The maintenance program addresses equipment testing and inspection and preventative maintenance schedules. 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 maintenance staff use a computerized maintenance management system to store equipment information, generate and prioritize work orders, schedule preventative maintenance (PM), provide safety procedures for work orders, and maintain an inventory of parts and materials. The computerized system is also used to generate work orders for preventative maintenanc
e. In addition to preventative maintenance, the staff performs corrective maintenance in the event of equipment malfunction or breakdown. Work orders indicate what safety precautions must be followed including whether lock-out/tag-out or confined space entry provisions are applicable.
3.6 Compliance Audit
The WTP will be required to complete periodic compliance audits for the RMP program. The primary goals of conducting an internal compliance audit are to gather sufficient data to verify compliance with RMP requirements and good process safety practices, identify process safety deficiencies and develop corrective actions, and increase safety awareness among plant staff.
The compliance audit methodology is modeled after Occupational Safety and Health Administration (OSHA) guidelines for conducting regulatory PSM compliance audits: Compliance Guidelines and Enforcement Procedures, OSHA Instruction CPL 2-2.45A (September 28, 1995). An internal compliance audit must be conducted at the
plant at least once every 3 years beginning June 21, 1999, for the chlorine process. A team that includes at least one person knowledgeable in the covered process and an audit leader knowledgeable in RMP requirements and audit techniques will conduct the audits. The audit team will promptly determine an appropriate corrective action for each deficiency identified during the audit and document the corrective actions and the dates by which they must be taken.
3.7 Incident Investigation
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 implement 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 b
ehavior 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 regarding 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 Director of Water and Wastewater Operations 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.
4.0 Emergency Response Program
The emergency response program details the procedures that will be followed in the event of a chlorine a release. EPA RMP regulation 40 CFR 68 Subpart E requires that an Emergency Response Plan be prepared. The Emergency Planning and Response Plan described in this section complies with the requi
rements of 40 CFR 68.95.
The Emergency Response Plan at the WTP is presented pictorially as a detailed flowchart prepared in such a manner that if a leak would occur it can be followed quickly and in a "user-friendly" manner. It provides for responding to accidental releases of chlorine and covers the response for a release from the initial alarm stage through either leak stoppage or hazardous material (HAZMAT) assistance; outlines evacuation of the WTP; and provides an outline for calling 911. In addition, critical plant operations are identified to ensure that, if possible, the critical functions are kept operational.