Coachman Point Water Treatment Facility - Executive Summary |
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The City of Eagan, Minnesota has prepared a Risk Management Plan (RMP) for the Water Treatment Facility located at 3419 Coachman Point; Eagan, MN 55122. The purpose of this plan is to help prevent or minimize risk of exposure to chlorine gas for both employees of the facility and also the surrounding community. I. FACILITY DESCRIPTION The Coachman Point Water Treatment Plant treats an average of 5 million gallons of water per day. The facility uses approximately 100 pounds per day of chlorine to disinfect the water system. During normal operations, the facility may have up to 8,000 pounds of chlorine stored at the site. The chlorine is stored in 2,000 pound containers. The facility is required to create a Risk Management Plan (RMP) in compliance with Environmental Protection Agency Regulation 40 CFR 68. The reason for this is the facility maintains more than 2,500 pounds of chlorine on site at any given time. Creation of the RMP also provides compliance with the Process Safety Management (PSM) requirement in OSHA Regulation 29 CFR 1910.119. II. SAFETY CONSIDERATIONS The Coachman Point Water Treatment Plant has a state of the art facility for safely handling and feeding chlorine into Eagan's water system. The system was put on line in 1984 and the facility has never experienced a major chlorine release. The feed system operates on a vacuum principle with automatic shut-off if the vacuum is interrupted. This minimizes the risk of a major release due to damage of the chlorine piping system. III. WORST CASE RELEASE SCENARIO The Risk Management Plan regulations require modeling the potential affects caused by the anticipated worst case chlorine release scenario. The worst case release scenario for the Coachman Point Water Treatment Plant is defined as: * Catastrophic failure of a 2,000 pound chlorine container due to corrosion, impact, etc. * 2,000 pound total chlorine release * 200 pounds/minute release * 10 minute duration * Atmospheric Stability C lass F * Wind Speed = 1.5 meters per second * Temperature of between 88 and 107 degrees Fahrenheit The influence radius of the worst case release is 2.63 miles according to EPA's Off-Site Consequence Analysis Guidance Reference Tables. The estimated population within the circle of influence is 38,000 based on Census numbers. There are several critical receptors within the influence circle including schools, residences, recreation areas, and major commercial/office areas. IV. ALTERNATIVE RELEASE SCENARIOS Alternative release scenarios more accurately reflect potential releases than the worst case scenario. Since alternative releases are more likely to occur, these scenarios are generally considered more useful for emergency planning. Two possible scenarios were considered for this facility. A. Alternative Release Scenario #1 The first alternative release scenario assumed the following conditions: * Tubing failure, bad connection or valve failure resulting in release of chlor ine gas through a 5/16" diameter opening * 317 pound total chlorine release * 10.5 pounds/minute release * 60 minute duration * Atmospheric Stability Class D * Wind Speed = 3.0 meters per second * Temperature of 77 degrees Fahrenheit The influence radius of this release scenario is 0.48 miles according to EPA's Off-Site Consequence Analysis Guidance Reference Tables. The estimated population within the circle of influence is 1,300 based on Census numbers. There are residences and recreation areas within the influence circle. B. Alternative Release Scenario #2 The second alternative release scenario assumed the following conditions: * Complete failure of a 1" diameter pipe causing a chlorine gas release from two 2,000 pound containers. * 634 pound total chlorine release * 23.4 pounds/minute release * 27.1 minute duration * Atmospheric Stability Class D * Wind Speed = 3.0 meters per second * Temperature of 77 degrees Fahrenheit The influence radius of this release scenario is 0 .72 miles according to EPA's Off-Site Consequence Analysis Guidance Reference Tables. The estimated population within the circle of influence is 2,850 based on Census numbers. There are residences and recreation areas within the influence circle. V. EMERGENCY RESPONSE PROGRAM Emergency response would be required in the extremely rare occurrence of a major chlorine release. The Coachman Point Water Treatment Facility is included in the Eagan community emergency response plan. In the event of an emergency chlorine release, an employee of the facility would be responsible for calling the Eagan Fire Department. The Fire Department would assess the situation and determine if the St. Paul HAZMAT team needs to be notified. These people are trained in handling emergency situations dealing with hazardous materials. The fire department and/or the HAZMAT team would be responsible for mitigating the effects of a release and coordinating evacuation procedures if necessary. A training prog ram has been established to insure all employees of the water treatment plant can identify an emergency situation and understand the procedure for notifying the proper authorities. As a part of this program, facility employees will annually meet with representatives of the fire department to discuss potential hazards. This will also allow the fire department to gain familiarity with the layout of the treatment plant and grounds. VI. IMPLEMENTATION OF THE RMP/PSM PROGRAM The facility has implemented written procedures in compliance with the RMP/PSM regulations to help minimize the risk of a chlorine release. The newly created RMP/PSM manual outlines training requirements, operating procedures, maintenance procedures, and defines responsible persons for implementing the different aspects of the plan. The RMP/PSM plan is a tool that will provide guidance for the facility in day to day operations thereby creating a safer and more effective work environment. |