Northport Water Treatment Plant - Executive Summary |
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The City of Northport, Alabama Water Treatment Plant is committed to the safety of its employees and the community at large by the use of current safety procedures and prevention programs in both day-to-day operations and in the event of a chemical release. The emergency action plan developed for the Northport facility applies to the use of chlorine in the water treatment process. The intent of the plan is to assist the City of Northport, Alabama in its efforts to preclude or mitigate episodic releases of chlorine that could result in the catastrophic loss of personnel and property within the facility and possibly the surrounding community. The Water Treatment Plant for the City of Northport, Alabama located at 11408 Lary Lake Road, is the primary source for potable water for the City of Northport. In the production of potable water, hazardous chemicals may be employed. At the Northport facility, chlorine delivered in 1-ton cylinders is used as the primary disinfecting ag ent. The chlorine is stored in the basement of the main administration and operations building at the Northport facility. The same properties that make chlorine valuable as a commodity also make it necessary to observe certain safety precautions in handling chlorine to prevent unnecessary human exposure, to reduce the threat to our own personal health as well as that of our co-workers, and to reduce the threat to nearby members of the community. It is our policy to adhere to all applicable Federal and state rules and regulations. Safety depends upon the manner in which we handle chlorine, the safety devices inherent in the design of this facility, the safe handling procedures that we use, and the training of our personnel. Chlorine has the following general properties: 1. Chlorine is a gas at room temperature. 2. Chlorine becomes an amber liquid at -29.3 degrees F. It is usually shipped as a liquid to conserve space. 3. Upon the release of chlorine from a containe r, it boils and becomes a greenish-yellow gas. 4. Chlorine has an irritating odor (bleach). 5. Chlorine is 2 1/2 times heavier than air, therefore, it usually gathers low to the ground. 6. Chlorine is soluble in water. It combines to form hydrochloric acid, which is highly corrosive. 7. NFPA hazard rating: Health - 3; Flammability - 0; Reactivity - 0; Special Hazard - Oxidizer Chlorine Health Hazards: 1. Minimum detection level for most individuals = 0.3 ppm. 2. At 3 - 6 ppm, chlorine causes irritation of the upper respiratory tract and mucous membranes. 3. The OSHA permissible exposure limit has a ceiling value of 1 ppm. 4. NIOSH has assigned 10 ppm as the IDLH value for acute chlorine exposure. 5. Exposure of skin and eyes can cause severe frostbite burns. 6. Acute health problems associated with chlorine gas include respiratory irritation, violent coughing, choking, nausea, dizziness, headaches, vomiting, chest pains, shortness of breath and p ulmonary edema. The Northport Water Treatment Plant has a maximum intended inventory of 10,000 pounds of chlorine (5 - 1 ton cylinders). At any given time, however, the inventory on hand is 8,000 pounds or less. All procedures involving the chlorine system, other than general inspections, involve at least two employees. Steps are taken to reduce the risk to employees and the local community alike, through the implementation of engineering and administrative controls in concert with appropriate regulations. In the event of a major chlorine release, the operators of the Northport Water Treatment Plant do not respond to stop the release directly. The facility's policy is very simple. In the event of an accidental release, the operator(s) are to: 1. Call 911. 2. Leave the site immediately. According to the appropriate regulations, this allows the Northport Water Treatment Plant to develop an emergency action plan instead of an emergency response program. The emergency action and evacuation plan for the Northport Water Treatment Plant was developed in order to meet OSHA requirements under 29 CFR 1910.38(a). The formal emergency evacuation plan is posted in readily visible locations throughout the plant. The plan has been discussed and coordinated with the Local Emergency Planning Committee, the Carroll's Creek Volunteer Fire Department and the City of Northport Fire Department. Chlorine release hazard control measures, engineering controls, administrative controls and personal protective equipment are being used to prevent the hazards that are associated with a chlorine gas release. These control measures originated and were applied in an effort to improve emergency response actions and to protect the emergency response personnel and the public at large. Existing Controls 1. Fixed Chlorine Monitor - Located in the chlorine storage room. Detects chlorine present in the air from 0-5 ppm. Upon detection, the monitor sou nds both an audible and visual alarm. 2. Personal Chlorine Monitor - Portable, personal monitors are available for use during gas release episodes. These monitors provide a way to quantitate the contamination levels. This allows for the determination of the proper type of personal protective equipment deemed necessary and zones for evacuation purposes. 3. Leak Testing - Leaks within the chlorine system are determined using ammonia solution. Chlorine will react with discharged ammonia vapor to produce a white cloud. 4. Emergency "B" Kit - This kit contains the required equipment to stop leaks at the valves, fusible plugs and in the wall of the cylinder (one-ton). 5. Buddy System - Activities involving the chlorine system, other than general maintenance, require a minimum of two workers to be present at all times. 6. Cylinder Handling Schedule - Chlorine cylinders are only manipulated during the day-shift. This allows for the proper number of persons to be present. Also, this relieves some of the difficulties that can be involved with the proper entities responding to a release during other times of the day. 7. Respiratory Protection Equipment - Respiratory breathing equipment for the Northport facility consists of two Self-Contained Breathing Apparatus (SCBA) backpack units. These units are to be used in atmospheres containing concentrations in excess of 3 ppm of chlorine. Under the RMP regulations the Northport facility developed a worst-case and an alternative release scenario. For this facility, the scenarios were as follows: 1. Worst-case Release Scenario. a. Models. i. A full chlorine cylinder is dropped during the loading/unloading process, outside the confines of the building, resulting in the rupturing of the cylinder or valve stem and the uncontrolled release of gas from the cylinder. ii. A fire in or near the chlorine room allowing the fusible plug to melt or a faulty plug in a cylinder. b. Parameters. i. Total amount released = 2,000 pounds of chlorine. ii. Release is in the form of a gas, which is heavier than air. iii. Release rate = 200 lbs./min. iv. Release duration = 10 minutes. c. Worst-case Area of Concern. i. Impacted radius = 1.3 miles (As determined using the Risk Management Program Guidance for Offsite Consequence Analysis (April, 15, 1999)). d. Offsite Impacts. i. Population. (1) Estimated residential population = 2,900 persons (using the most recently available census data). (2) Carroll's Creek Baptist Church, Carroll's Creek Volunteer Fire Department, Macedonia United Methodist Church, and the Forest Glen recreation area. ii. Environmental. (1) No environmental receptors were identified within the impacted area. 2. Alternative Release Scenario. a. Models. i. The yoke on the cylinder valve is defective, malfunctions or is imporperly installed onto a chlorine cylinder, resulting in an uncontrolled leak. ii. The valve packing leaks, or the yoke is not properly seated or tightened on the cylinder valve, resulting in an uncontrolled release from the cylinder. b. Parameters. i. Total amount released = 2,000 pounds of chlorine. ii. Released in the form of a gas, which is heavier than air. iii. Release rate = 83.53 lbs./min. iv. Release duration = 24 minutes. c. Alternative Release Area of Concern. i. Impacted radius = 0.2 miles (As determined using the Risk Management Program Guidance for Offsite Consequence Analysis (April, 15, 1999)). d. Offsite Impacts. i. Population. (1) Estima ted residential population = 70 persons (using the most recently available census data). (2) No impacted institutions. ii. Environmental. (1) No environmental receptors were identified within the impacted area. The general accidental release prevention program and chemical-specific prevention steps: This facility complies with EPA's Accidental Release Prevention Rule and with all applicable state codes and regulations. This facility is also operated in accordance with recommendations from the Chlorine Institute. The facility employs detectors and alarms to notify employees of problems for the purpose of causing a more rapid response time. The chlorine feed system is a vacuum type employing valves that close automatically in the event of a loss of vacuum. The alarms are equipped with a battery backup to ensure protection even in the event of a power outage. The Northport Water Treatment Pl ant has not had an incident involving chlorine since the process was begun in 1990. In the unlikely event of a major release, the operator(s) at the Northport Water Treatment Plant are notified with audible alarms both inside and outside the facility. Upon hearing this alarm, the operator(s) will dial 911 and leave the site. Following the initial call, the notified first responders will arrive from the Carroll's Creek Volunteer Fire Department. The responders will notify the Local Emergency Planning Commission, who will then notify the public as deemed necessary. Employees are trained to quickly determine the level of emergency and thus the appropriate response. They are also instructed and drilled in the emergency evacuation plans for the facility. The Northport Water Treatment Plant has made a commitment to continue to improve safety and plant operations in accordance with appropriate guidelines. The alarm system is currently being upgraded to ensure even greater protection for the employees and the public. |