City of Benton Harbor Water Plant - Executive Summary |
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The City of Benton Harbor Water Plant (BHWP) facility staff are committed to safety and are continually evaluating ways to improve safety programs. Facility staff work closely with other city and county agencies to coordinate safety and emergency response training activities. The Berrien County HAZMAT team conducts annual training exercises for responding to accidental chlorine releases. The BHWP uses chlorine, a regulated substance, in 1-ton cylinders to purify drinking water for the City of Benton Harbor, Michigan. The cylinders are used and stored indoors to protect them from the weather and to help limit the release rate in the unlikely event of a chlorine leak. Chlorine sensors continuously monitor the air in the rooms where chlorine is used and stored. If more than 1 ppm of chlorine is detected, an alarm sounds alerting facility personnel to a possible leak. In 1990, the BWHP installed new vacuum controlled chlorine process equipment to reduce the potential for an accident al release of chlorine gas. A loss of vacuum in the chlorine process lines automatically closes the valve at the chlorine supply cylinder. The worst-case release scenario was modeled according to EPA guidlines and involved the catastrophic failure of one, full 1-ton cylinder. No mitigation measures were considered for this scenario. It is not likely that such an event would occur. EPA also requires that five alternative release scenarios be considered and that one more likely to occur than the worst-case scenario should be used in an off-site consequence analysis. The facility has no history of chloine releases under EPA'a alternative release scenarios. Chlorine is introduced into the process through a vacuum controlled regulating valve on the cylinder in service. If the vacuum is lost for any reason, the valve will automatically close preventing a release of chlorine gas. For purposes of this Risk Management Plan (RMP), it is assumed that the gasket between the vacuum controll ed regulating valve and the chlorine cylinder fails, causing a release of chlorine gas. Since such a leak would occur indoors, it was estimated the release rate to the outdoors would be reduced to 55%. It is not likely that this alternative release scenario would occur. The BHWP has safely operated the present chlorine process equipment, without incident, since it was installed May 15, 1990. The facility is continually evaluating ways to improve the safety of this chlorine system. The facility recently prepared a new emergency response plant that included procedures for evacuating employees and notifying the local HAZMAT team in the event of a chlorine release. The facility is covered by the Berrien County Local Emergency Planning Committee's emergency response plan and has procedures for notifying local emergency responders in the event of an accidental release of chlorine. |