Fridley Filter Plant - Executive Summary
Executive Summary |
Chemicals are widely used in industry, in the home, and in the environment. They are transported on roads, water, and railways. The Minneapolis Water Works' (MWW) Fridley Complex stores chemicals that it uses in its daily operations. The Fridley Complex includes the Fridley Filter Plant (FFP), which uses chlorine stored in up to two 90-ton railroad tank cars and five 1-ton containers, and anhydrous ammonia stored in 6,000-gallon and 1,000-gallon bulk storage tanks. Chlorine and ammonia are used at the FFP to disinfect treated water prior to distribution to customers in Minneapolis and surrounding communities. The natural world contains more that 1,500 chlorine-containing compounds. Chlorine is also used to disinfect wastewater, disinfect our swimming pools and protect human health through the destruction of disease-causing organisms. The World Health Organization estimates that 25,000 children who die daily could be saved through the use of an effec
tive water disinfection agent such as chlorine.
Chlorine and ammonia are non-explosive and non-flammable. However, they support combustion under some circumstances. They are both respiratory irritants, and exposure through inhalation or eye or skin contact can pose a health risk. As a precaution, the FFP has special safety systems that are an integral part of the chlorine and ammonia systems.
We take our safety obligations in storing and using chemicals as seriously as we take providing the community with safe purified drinking water. The following document describes the steps we take everyday to ensure a safely operating plant, what could happen if there was an accidental release of a chemical stored on site, and what to do in the event of an emergency.
Accidental Release Prevention and Emergency Response Policies
This document complies with the U.S. Environmental Protection Agency's (EPA's) Risk Management Program, codified under Section 112 (r) of the Clean Air Act (CAA) Amendm
ents of 1990, 40 Code of Federal Regulations (CFR) Part 68. The Risk Management Program requires facilities that use certain substances above certain quantity thresholds 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. This plan is referred to as the Risk Management Plan (RMP).
Chlorine and ammonia are stored in quantities above the regulatory thresholds at which a RMP is required. This RMP document summarizes our existing safety systems, policies, procedures, and on-going actions that are designed to prevent or minimize impacts of accidental releases of chlorine or ammonia to the environment.
The Fridley Complex has a detailed and comprehensive emergency response plan to handle accidental releases. In addition, MWW staff were closely involved in the formation of the Fridley Community Awareness and Emergency Response (CAER) unit in 1993. The group has
since expanded to include several surrounding communities and is now referred to as North Metro CAER unit. The purpose of CAER is to integrate existing emergency response plans and procedures of local industry and the public safety organization. The North Metro CAER unit includes the Fridley Complex and the Fridley Fire Department. The organization maintains updated emergency databases, plans drills and special events, develops training programs, and shares information to improve response procedures.
The Fridley Complex has been handling chemicals since 1925. To date, no chlorine or ammonia releases causing a safety or health hazard affecting the surrounding community have occurred. Minor releases that have occurred at the plant have been safely remedied using existing emergency response procedures and techniques.
Understanding the Chemicals Used at the Fridley Complex
The Fridley Complex, operating since 1925, is located at 4300 Marshall Street NE in Minneapolis, Minnesota.
Raw water supplied from the Mississippi River is treated at the Fridley Softening Plant and the FFP, and treated water is distributed to customers in Minneapolis and the surrounding communities. The water treatment process includes screening, softening, coagulation, filtration, and disinfection. The MWW produces an average of approximately 70 million gallons of water per day from all of their treatment plants. The FFP has a chlorination system that uses chlorine gas fed from liquid chlorine storage containers and an anhydrous ammonia system that uses ammonia gas fed from liquid anhydrous ammonia storage containers.
The railroad tank cars containing chlorine are delivered to the Plant by rail. Chlorine is also stored in 1-ton containers as a backup. Liquid chlorine is withdrawn directly from the rail car or 1-ton containers and delivered to the disinfection process. Liquid ammonia is brought to the plant by the chemical supplier and is transferred to the bulk storage tanks. Liqu
id ammonia is also withdrawn from the bulk storage tanks and delivered to the disinfection process. The FFP uses state-of-the-art equipment to maximize the safety for plant staff and the community at large. Some of the specific features are as follows. Chlorine and ammonia leak detectors continuously monitor for leaks in the bulk storage areas and in the chlorine and ammonia process areas. Leak alarms activate an audible alarm throughout the plant and the alarms sound at the central and local control panels.
Other alarms on the chlorine system include high pressure in liquid piping, evaporator malfunction, low vacuum at the chlorinator, and low injector water pressure. These alarms sound at the chlorine central and local control panels. Process related factory-set pressure relief valves are included to protect the integrity of the equipment. Pressure relief valve discharges are continuously monitored by leak detectors that sound an alarm when activated. Chlorine rail cars inclu
de automatic shutoff valves. The rail car discharge valve will automatically close in response to a leak alarm, a sudden loss in line pressure, or a power outage.
The chlorine and ammonia process rooms are enclosed in a building and the process areas are equipped with ventilation systems. The chlorine process area includes an automatic ventilation system that operates when the chlorine leak detector detects chlorine in the room.
The Fridley Complex is surrounded by a fence and access to the plant is limited to a few gates. A surveillance camera is provided in the chlorine rail car area that is monitored by plant operators at the operator workstation. The plant is staffed 24 hours per day, 365 days per year.
The RMP consists of three major parts. The first part is the Hazard Assessment. The Hazard Assessment is done to determine the potential effects that a release of a regulated substance could have on the public surrounding the facility. The second part is a Pre
vention 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 regulations are very similar, the Prevention Program and the Emergency Response Program also serve as the OSHA Process Safety Management (PSM) plan, and this document is therefore is referred to as the RMP/PSM plan.
For the Hazard Assessment, the distance a set endpoint concentration of chlorine or ammonia gas would travel was determined. In addition, an estimate of the population that could be affected by a release of chlorine or ammonia was determined, and sensitive receptors were identified. The Hazard Assessment considers two release scenarios-a "worst case" and an "alternative case."
The regulations require the development of a worst-case release scenario based on con
servative assumptions. For example, the FFP is required to assume that the entire contents of the largest single container of chlorine or ammonia will be released in 10 minutes. In addition, only "passive" mitigation methods such as buildings or dikes can be considered when determining the distance the release could travel. Passive mitigation, as defined, requires no mechanical, electrical, or human input. However, in many scenarios mitigating the release by isolating the process could reduce the amount released. In addition, the worst-case scenario requires that very stable atmospheric conditions be assumed which results in a large area of impact. These conservative assumptions were set by EPA to ensure public notification and ensure that local emergency response planning takes into account the greatest possible impacted area surrounding the release point.
The scenario used for chlorine at the FFP is the rupture of a 90-ton railroad tank car, resulting in a release of 180,000 pounds o
f chlorine over a 10-minute duration. For ammonia, the worst-case scenario is the rupture of a 6,000-gallon storage tank, resulting in a release of 26,000 pounds over a 10-minute duration. The released liquid is assumed to quickly volatilize and disperse as a vapor cloud. The hazard assessment requires that the "toxic endpoint" or distance from the point of release to a location at which the chemical concentration equals or exceeds a certain concentration must be determined. The distance to the toxic endpoint was estimated using the EPA-approved DEGADIS BreezeHaz(tm) DEGADIS+ 2.0 gas dispersion model. That concentration is defined as the maximum airborne concentration below which individuals could be exposed for up to 1 hour without experiencing or developing irreversible or other serious health effects, or symptoms that could impair an individual's ability to take protective action.
In practice this type of total release of a bulk tank would be unlikely and probably never occur dur
ing the lifetime of the plant. The results of the dispersion modeling analysis for the chlorine and ammonia worst-case release scenario indicate that the release extends to a 5.2-mile radius for chlorine and a 0.8-mile radius for ammonia.
The RMP rule also requires that at least one alternative release scenario be evaluated for chlorine and ammonia. The alternative scenarios reflect a type of release that is more likely to occur compared to the worst-case scenario. Unlike the worst-case scenario, the alternative release scenario may consider "active" mitigation such as shutoff valves and a more realistic release quantity and release rate. Active mitigation is defined as requiring mechanical, electrical, or human input. Lastly, it assumes local, typical meteorology, which is more realistic than the conservative meteorological conditions that must be assumed for the worst-case scenario. The scenario used for chlorine was a leak in the liquid chlorine pipe leading fr
om the rail car to the evaporator. Under this scenario, the amount of chlorine released was calculated to be 248 pounds. The same modeling approach was used as for the worst-case release scenario, except meteorological conditions were adjusted to more likely local conditions.
The scenario used for ammonia assumes that anhydrous ammonia is released from a small leak or crack in the liquid process piping, valves, or joints. Under this scenario, the amount of ammonia released was calculated to be 1,866 pounds. Meteorological conditions were adjusted to more likely local conditions.
The results of the dispersion modeling analysis for the chlorine and ammonia alternative case release scenario indicate that the release extends to a 0.2-mile radius for chlorine and a 0.1-mile radius for ammonia.
The Prevention Program consists of 12 elements designed to improve the system safety and decrease the likelihood of a release.
The participation of the
MWW 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.
Plant staff participated in the development of the Prevention Program through a series of meetings and workshops. Another way that the MWW staff participated in the development of the RMP/PSM was the Process Hazard Analysis that is described below.
Process Safety Information
The RMP/PSM regulations require that information concerning process chemicals, technology, and equipment be compiled as part of the RMP program. Emergency response planners can use such information to develop training programs and procedures, or as a general resource. The information is also supplied to contractors who will work in the chlorine and ammonia process areas as part of the requirements outlined in the
Contractors element of this program. All the required process safety information was compiled as stated in 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 systematically to evaluate potential causes and consequences of accidental releases. This information was used by FFP staff to improve safety and reduce the likelihood and potential consequences of an accidental release. 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 and ammonia processes.
The chlorine and ammonia PHAs were conducted by an interdisciplinary team of plant staff familiar with process operation and maintenance. 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 plant were identified. Several changes have been adopted by the plant and incorporated as part of the overall RMP/PSM program. Other improvements and process modifications to reduce or eliminate potential hazards are scheduled to be implemented or incorporated.
Operating procedures for the chlorine and ammonia processes have been developed as part of the RPM/PSM plan. 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.
An effective RMP/PSM training program can significantly reduce the potential for accidental release incidents. Employees involved in operating or maintaining the chlorine or ammonia processes must receive tra
ining that includes applicable operating and maintenance procedures and an overview of the process. Training must emphasize safety and health hazards and safe work practices.
FFP staff receive initial training on the operations and maintenance of the chlorine and ammonia processes. In addition to RMP/PSM plan training, select 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 FFP must make contractors aware of the known hazards of the chlorine and ammonia processes related to the contractors' work. In addition, the plant must make contractors aware of the applicable elements of its emergency response plan. The FFP must evaluate contractors' safety programs and select only those that can perform work on or adjacent to the chlorine or ammonia processes without compromising the safety and health of employees at the facili
ty or the surrounding public.
Before allowing a contractor to work on or adjacent to the chlorine or ammonia processes, the plant must obtain and evaluate information regarding the contractor's safety performance and programs. If a contractor is to work in or adjacent to any hazardous chemical, a safety briefing, to make the contractor aware of the plant's RMP/PSM plan requirements, must be conducted before work begins.
A pre-startup safety review must be conducted for any new process that uses a regulated substance under RMP, or for significant modifications to the existing chlorine or ammonia processes 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 review. The purpose of the pre-startup safety review is to ensure that the facility is ready to operate new and modified regulated processes safe
To initiate the pre-startup safety review, all updated elements of the RMP/PSM 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 an accidental release. The mechanical integrity program also addresses equipment testing and inspection, preventative maintenance schedules, and personnel training. The intent is to ensure that equipment used to process, store, or handle chlorine and ammonia is maintained and installed to minimize the risk of
The FFP maintenance staff schedule preventative maintenance (PM), provide safety procedures for work orders, and maintain an inventory of parts and materials. In addition to preventative maintenance, the plant staff performs corrective maintenance in the event of equipment malfunction or breakdown. The staff that perform maintenance tasks are all trained as part of the RMP/PSM program.
Hot Works Permits
RMP/PSM regulations require employees and contractors to employ safe work practices when performing "hot work" in, on, or around the chlorine or ammonia processes. 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 a
re appropriate, and then initiate the safeguards necessary to ensure a fire-safe workplace. Following the standards outline in this section aid in complying with the OSHA Hot Work Regulations (29 CFR 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 or ammonia systems will be reviewed before they are implemented to determine 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 operating 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 implem
entation. A Management of Change Committee that consists of plant engineering, operations, and/or maintenance staff is formed to evaluate any modifications that are covered under the RMP/PSM. The committee will complete a Management of Change Form that must be reviewed and authorized prior to initiation of a covered change.
Each incident that resulted in or could reasonably have resulted in a catastrophic release of chlorine or ammonia 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, facility management will establish an investigation team. As part of the investigation, the investigation team will prepare an incident report to recommend system changes.
The FFP is required to complete a compliance audit for the RMP/PSM program. The primary goals of conducting an internal compliance audit are to gather sufficient d
ata to verify compliance with RMP/PSM requirements and good process safety practices, identify process safety deficiencies and develop corrective actions, and to increase safety awareness among plant 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 (September 28, 1995). An internal compliance audit must be conducted at the plant at least once every 3 years for the chlorine and ammonia processes. 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. Plant management and 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.
Emergency Response Program
The Emergency Re
sponse Program develops 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 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 provides specific emergency response procedures for accidental releases of chlorine or ammonia. The emergency response procedures cover a release from the initial alarm stage through either leak stoppage or assistance from an outside hazardous materials response team. As part of the emerg
ency response procedures there are plans for victim rescue, leak investigation, and communication with additional support agencies. The Emergency Planning and Response plan also indicates the level of training needed to carryout the emergency response procedures.
Information regarding self-contained breathing apparatus is provided in the Emergency Planning and Response plan. It also addresses plant site communication, emergency response equipment, first aid and medical treatment, medical surveillance and consultation, and emergency response drills. Plant personnel routinely communicate with emergency personnel in the surrounding jurisdictions through participation in the North Metro CAER unit. The North Metro CAER unit, which includes the Fridley and Columbia Heights Fire Departments, is aware of the chemicals stored and used on site, and have included this information when developing emergency plans for areas impacted off site.
In conclusion, MWW and the FFP have taken all necessary
steps to prevent the release of hazardous chemicals that may harm facility staff or the surrounding public.
FRIDLEY FILTER PLANT
EXECUTIVE SUMMARY RISK MANAGEMENT PROGRAM