Pyramid Peak Water Treatment Plant - Executive Summary |
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Executive Summary In June 1996, the U.S. Environmental Protection Agency (EPA) issued Risk Management (RM) program regulations (40 CFR, Part 68). Regulated under the Clean Air Act Amendments (CAAA), Section 112(r), the RM program requires facilities that store large amounts of listed hazardous chemical substances to prepare and implement risk management plans to reduce the probability of accidental releases and minimize the health risks to the public and the environment. The RM program regulates 77 listed toxic substances and 63 listed flammable substances. Of the 140 toxic and flammable chemicals regulated by the RM program, the Pyramid Peak Water Treatment Plant (PPWTP) has only one such listed chemical, anhydrous chlorine, that is used to disinfect drinking water provided to the residents of Glendale. The terms anhydrous chlorine and chlorine are used interchangeably and specifically refer to a chemical listed in the RM program regulations. When used as a disinfectant, chl orine prevents the spread of waterborne diseases and has been used for years in the water treatment industry. When properly used, chlorine has proven to be both safe and effective. In addition to the PPWTP, the RM program regulations apply to an estimated 7,200 public and private drinking water and wastewater treatment facilities nationwide where chlorine and/or ammonia are used as disinfectants. As with other facilities across the U.S., the City of Glendale views the RM program as a vehicle to communicate emergency response procedures to the public and emergency planning agencies. Minimizing Risk The major driving force in the development of the RM program regulations is reducing the risk to public health by minimizing the potential of a chemical release. At PPWTP, there is a multi-layer system in place to meet this goal. The RM program includes the following: (1) properly trained operators to safely handle chlorine; (2) chlorine detectors located where chlorine is stored and /or used; (3) failsafe equipment design and installation of back-up safety equipment including emergency scrubbers; and (4) an automated warning system that notifies both on-site and off-site personnel of a potential release. Trained personnel respond to chlorine alarms to assess whether a chlorine release poses an imminent danger to employees or the public. While a significant release is unlikely, emergency response plans have been developed for just such an occurrence. The emergency response plans include procedures to be followed by operators trained to take appropriate action including contacting the Glendale Fire Department (GFD). The GFD's emergency response time to the PPWTP is 10 minutes. Management Plan Within the management and administrative roles of the PPWTP, responsibility has been defined to coordinate and implement the RM program. Overall development and management of the RM program is the responsibility of the RM Program Manager. The RM Program Coordinator repor ts to the RM Program Manager and is responsible for coordinating the implementation of the RM program. The PPWTP Safety Administrator is responsible for the overall recordkeeping of the RM Program and assisting the RM Program Coordinator. The Senior Operator is responsible for the day-to-day implementation of the RM program and reports to the RM Program Coordinator. Additional program oversight is provided by the City of Glendale's Environmental Resource Administrator and Employee Safety Manager who act as external auditors of the program's implementation and overall quality. For the PPWTP, the following personnel have been assigned to coordinate and implement the RM program: * The Superintendent of Plant Operations is the designated RM Program Manager * The Plant Operations Supervisor is the designated RM Program Coordinator The Plant Operations Supervisor is also the delegated coordinator for the Occupational Safety and Health Administration (OSHA) Process Safety Management (PS M) program in place at PPWTP. The requirements of the PSM program largely parallel RM program requirements. Because of the similarities in the two programs, the RM Program Coordinator will be referred to as the RM/PSM Program Coordinator throughout this document. Worst Case and Alternate Case Release Scenarios PPWTP modeled two potential release events for chlorine and followed EPA guidance to identify a worst case release scenario (WCS) and alternate case release scenario (ACS) as defined by the EPA regulations. Toxic endpoints were identified using EPA-approved methods. A "worst case scenario" is defined by the EPA as the result of a release from the largest container and/or pipe over a span of 10 minutes. The distance to a toxic endpoint is defined by emergency response planning guidelines level 2 (ERPG-2) as a concentration a person can be exposed to for up to 1 hour without experiencing serious health effects. The distance to a toxic endpoint is used to determine the affec ted geographical area and population for emergency planning purposes. The ERPG-2 value for chlorine is 3 parts per million by volume (ppmv). EPA states that a WCS is useful for encouraging "community dialogue". However, because the WCS does not necessarily represent events likely to occur, it is more useful for discussion purposes than for emergency planning purposes. An "alternative release scenario" is a release scenario more likely than the WCS and should be used for emergency response planning. The WCS for the PPWTP is a release of 2,000 pounds of chlorine in 10 minutes. The distance to the toxic endpoint for the WCS is 2.25 miles, affecting approximately 16 square miles and an estimated population between 1500 and 2000. The alternate case release scenario (ACS) for chlorine was evaluated for emergency response planning purposes. The ACS is based on an operator opening the chlorine container valve before connecting the flexible piping (pigtail) resulting in a release of gas eous chlorine. This ACS resulted in an endpoint distance of 0.53 miles. A population of approximately 150 to 200 in an area less than 1 square mile could potentially be affected if this scenario were to occur. 5-Year Accident History Since PPWTP opened in 1986, there has not been a release resulting in off-site property damage or health consequences requiring medical treatment. Chemical Release Prevention Program The PPWTP has a chemical release prevention program in place for the chlorine process. This program is required by both the RM program and OSHA PSM regulations. The prevention program for the chlorine process has been in place since 1995. Key provisions of the PPWTP prevention program are as follows: * Written procedures have been prepared for the covered process, including directions for safe start-up and shutdown operations and emergency shutdown. * PPWTP employees who operate the chlorine system must receive training initially and periodically on safe start-up an d shutdown operations and emergency shutdown. * Incidences, including minor releases are investigated to improve the safety of the process. * Once completed, incident investigations are shared with employees. * Employees participate in a process hazard analysis (PHA) which identifies potential hazards and ways to improve the safety of the process every five years, or when significant changes are made to the process. * The PPWTP has a management of change (MOC) program in place that mandates changes to the chlorine system are reviewed prior to the change to ensure that the change will not compromise safety. * An equipment design and maintenance program is in place that assures mechanical integrity. Equipment design and maintenance practices are consistent with guidance provided by the Chlorine Safety Institute. * A preliminary start-up review is also completed prior to returning the covered equipment to service after a major change or prior to a new covered process coming o n-line. * A hot work permit program is in place. * Contractors who work on or near the RM program process are advised of the hazards of chlorine, provided evacuation instructions in case an incident occurs, and must certify that they are qualified to work near hazardous materials. Emergency Response Program The PPWTP has an emergency response program in place for the chlorine process. This program consists of personnel trained to recognize releases, assess the situation, and engage the proper emergency response personnel. When external emergency response is required, plant personnel will notify the GFD then establish an incident command system that is transferred to the GFD upon their arrival. Once GFD establishes command, it is supported by PPWTP personnel familiar with the affected process. The GFD has access to additional emergency response resources, including the City of Glendale Police Department, Red Cross, Arizona Department of Environmental Quality, and other agencies , as needed. |