MS Highway 613 Water Well - Executive Summary
RISK MANAGEMENT PLAN |
MS HWY. 613 WATER WELL
CITY OF MOSS POINT, MS
Escatawpa Utility District (EUD) is a relatively large public utility district providing waterworks, wastewater, natural gas, and fire protection services for a large rural and suburban area in eastern Jackson County, Mississippi, north of the City of Moss Point and east of the Pascagoula River. The City of Moss Point owns and operates Escatawpa Utility District.
The EUD MS Hwy. 613 water well is located in a predominantly rural area about 1.5 miles north of the corporate limits of the City of Moss Point. The site includes a 200 gpm water well, a 125,000 gallon elevated steel water storage tank, a small equipment building with chlorination equipment and two one ton cylinders of gaseous chlorine.
REGULATED SUBSTANCES HANDLED
The regulated substance handled at the EUD Hwy 613 well site is highly toxic gaseous chlorine stored in two, one-ton, steel tanks. This chlorine is used to oxidize hydrogen sulfide and disinfe
ct raw well water as it is pumped into the water distribution system.
The chlorine in the steel tanks is stored under pressure and liquidfied. An accidental release would result in gaseous chlorine escaping into the atmosphere. Chlorine gas is heavier than air and would tend to spread out near the ground surface. Therefore, a large scale accidental release represents a serious health and safety hazard to people and animal life in the area surrounding the well site.
ACCIDENTAL RELEASE EMERGENCY RESPONSE POLICIES
EUD waterworks personnel monitor the MS Hwy. 63 well site on a daily basis although there are no personnel assigned to the site full-time. During these short monitoring visits chlorination equipment is checked for proper operation, leaks, or other malfunctions. Any malfunctions posing health or safety hazards are immediately reported to public works headquarters by radio.
Preventive maintenance activities are also undertaken periodically to replace deteriorating chlor
ination equipment. EUD recently initiated a program to place fiberglass enclosures over the chlorine cylinders and roller trunions under the cylinders. The enclosures protect the cylinders, regulators, piping and related equipment from the elements. These enclosures, while not airtight, will assist in containing chlorine leaks on-site and will protect the chlorine containers from physical damage that could result in a ruptured tank. The roller trunions allow a tank that is leaking to be rotated so that liquified chlorine is not spilled.
EUD personnel's emergency response to chlorine leaks is to immediately notify public works headquarters by radio and make every effort to contain the accidental release. Public works headquarters immediately notifies the Moss Point Fire Department (Fire Marshall is the Civil Defense Director). The Moss Point Fire Department notifies the Jackson County LEPC, mobilizes the Moss Point Police Department, Jackson County Sheriff's office, and Moss Poin
t Public Works Department and immediately begins appropriate emergency actions such as public notification, isolation and evacuation of the danger area, and repair of the damaged chlorine facilities.
WORSE-CASE RELEASE SCENARIO
The worse-case accidental release scenario is based upon the rupture of one chlorine tank and the release of 2000 pounds of gaseous chlorine over a period of ten minutes at the rate of 200 pounds per minute. The RMP/Comp computer program furnished by EPA notes that an area with a radius of 2.2 miles centered on the well site would be impacted by this accidental release.
The City of Moss Point estimates that this worse-case accidental release would pose a hazard to about 1000 people in the 2.2-mile radius before the chlorine gas had dissipated enough to be non-hazardous.
The 2.2-mile area around the well site would immediately be cordoned-off by law enforcement personnel and all people would be evacuated from the area, except properly equipped and protecte
d emergency personnel.
ALTERNATIVE RELEASE SCENARIO
The worse-case accidental release scenario noted above is an unlikely event. Based upon past history, a more likely event is a slow chlorine leak from a partially filled tank. Therefore, the alternative release scenario is based upon the accidental release of 1,000 pounds of gaseous chlorine over a period of two hours at the rate of about eight pounds per minute. The toxic endpoint of this accidental release would extend for about 0.2 miles from the well site.
The city estimates that about 200 people would be impacted by this scenario. The same emergency measures would be undertaken as for the worse case scenario, except that the evacuation area would be reduced from 2.2 miles to 0.2 miles.
ACCIDENTAL RELEASE PREVENTION PROGRAM
EUD personnel comply with OSHA 1910.36 (Emergency Action Plan) and coordinate accidental release prevention activities with the Moss Point Public Works Department, Fire Department and Civil Defense Dir
ector, the City Engineer, and the Jackson County LEPC. EUD and Moss Point Public Works personnel perform routine checks and preventive maintenance activities designed to prevent accidental release of chlorine gas.
FIVE YEAR ACCIDENT HISTORY
There has been one accidential release of gaseous chlorine from the MS Highway 613 water well site in the last five years. This accidental release occurred on June 16, 1998. It was discovered at 4:23 am and was terminated at 6:25 am. The leak was caused by a deteriorated chlorine pressure regulator valve and allowed about 1000 pounds of chlorine to leak from a one-ton cylinder over a period of about two hours. The Moss Point Fire Department and local law enforcement personnel cordoned-off a one-quarter mile area around the well site and evacuated all people from the area. There were no casualties to residents or emergency personnel.
EMERGENCY REPONSE PROGRAM
The EUD's emergency response program currently consists of notifying the Moss Poin
t Fire Department and Civil Defense of the accidental release and taking actions as appropriate to contain the leak, cordon-off the area around the well site, and evacuate people in the affected area as ordered by the Fire Department.
The City Engineer, Public Works Director, Fire Marshall (Civil Defense Director), and Police Chief plan to hold a series of meeting to review preventive maintenance activities, safety procedures, emergency response policies and procedures, and other health and safety issues at all of the EUD and municipal well sites where chlorine is stored.