MCB Quantico Mainside Water Treatment Plant - Executive Summary
EXECUTIVE SUMMARY |
1. Accidental release prevention and emergency response policies:
a. This Risk Management Plan has been developed for Marine Corps Base (MCB) Quantico to address the accidental release of chlorine from the Mainside Water Treatment Plant (MWTP). The plan focuses on hazard assessment, a prevention program, and emergency response procedures. MCB Quantico is concerned about the impact day-to-day operations have on the environment. Pollution caused by a hazardous substance release can have detrimental effects on people and the environment if proper steps are not taken to prevent, contain and effectively clean up such occurrences in a timely and efficient manner. To address this, the base is dedicated to establishing measures that prevent hazardous substance spills by incorporating a unified approach that integrates technologies, procedures, and management practices. It is the policy of this command to mini
mize the release of hazardous substances from storage tanks, piping, valves, transfer areas, and work spaces on base and to provide efficient and speedy containment and cleanup procedures if spills do occur.
b. The plan combines all of the Federal, Commonwealth of Virginia, and United States Marine Corps regulatory requirements pertaining to the development of a Risk Management Plan for hazardous substance spills involving chlorine at the MWTP. A cross-referencing section is provided and allows the user of this plan to quickly locate applicable regulatory sections within the plan. This plan serves as a statement of command policy and intent, as well as a working document for those concerned with the prevention and control of spills.
2. The stationary source and regulated substances handled:
a. The primary purpose of the MCB Quantico MWTP is to produce potable water for that portion of the base that is east of Interstate 95 and Quantico Town. The MWTP can produce 2 million gallons p
b. The MWTP is located at 1303 Caddy Road, Quantico, Virginia a few hundred meters east of northbound Interstate 95. Chlorine gas is received from a private vendor for both the 1-ton and 100-lb cylinders every two months. There are five, 1-ton cylinders and approximately twenty-five, 100-lb cylinders on station. The 1-ton cylinders are unloaded by truck using a truck-mounted hoist. They are usually deposited in front of the 1-ton cylinder storage area. MWTP personnel then use the on-site traveling hoist to place the 1-ton cylinders in position inside the chlorine storage area. The facility includes a chlorination room, which contains liquid chlorine containers, a chlorinator, and various safety equipment and an instrument room, which includes a flow recorder, various electrical panels, and additional safety equipment.
Access to the site is restricted to authorized facility employees, management personnel and contractors. The facility is manned during the day and with two oper
ators on station after duty hours.
3. The worst-case release scenario(s) and the alternative release scenario(s), including administrative controls and mitigation measures to limit the distances for each reported scenario:
a. The offsite consequence analysis includes consideration of two chlorine release scenarios, identified as "worst case release" and "alternative scenario." The first scenario is defined by EPA, which states that "the owner or operator shall assume that the . . . maximum quantity in the largest vessel . . . is released as a gas over 10 minutes," due to an unspecified failure. The alternative scenario is defined as "more likely to occur than the worst-case release scenario."
b. Atmospheric dispersion modeling has to be performed to determine the distance traveled by the chlorine released before its concentration decreases to the "toxic endpoint" selected by EPA of 3 ppm, which is the Emergency Response Planning Guideline level 2 (ERPG-2). This is defined by the Ame
rican Industrial Hygiene Association (AIHA) as the "maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms which could impair an individual's ability to take protective action." The residential population within the circle with a radius corresponding to the toxic endpoint distance has to be defined "to estimate the population potentially affected."
c. The worst-case release scenario at the MCB Quantico Water Treatment Plant involves the failure of a 1-ton cylinder (2,000 pounds of chlorine). The offsite consequence analysis for this scenario was performed using conditions pre-defined by EPA, namely release of the entire amount as a gas in 10 minutes, using the one-hour average ERPG-2 as the toxic endpoint, and consideration of the population residing within a full circle with radius corresponding to the toxic endpoint distance.
EPA set these conditions to facilitate the performance of the offsite consequence analysis.
d. EPA mandated meteorological conditions, that is, Stability F, wind speed of 1.5 m/sec, average air temperature of 77 degrees, and average humidity (65%) were used.
e. When atmospheric dispersion modeling for the worst case scenario was performed using the EPA assumptions, the distance to the toxic endpoint was 1.3 miles with the following public receptors impacted: in Stafford County, residences, Fritter Park, commercial, office, and industrial areas in Boswells Corner; in Prince William County, Locust Shade Park; at MCB Quantico, the commissary, exchange, service station, and one-half of the government housing at Lyman Park.
f. The alternative release scenario involves the rupture of the flexible connection (pigtails) connected to the 1-ton containers, possibly due to an earthquake. The amount of chlorine released is 1,000 lbs, at an average rate of 100 lbs/min. Toxic endpoint distances
to ERPG-2 levels were obtained. The typical meteorological conditions used were Stability D, wind speed 3.0 m/s, average air temperature of 77 degrees Fahrenheit, and 63% average humidity. The estimated distances traveled to the toxic endpoints are 0.2 miles for the ERPG-2 with no public receptors impacted.
g. Actuation of the chlorine detector is an active mitigation measure considered in the worst case release scenario(s). An additional mitigation system installed is the conversion of the existing chlorinators to a remote vacuum type, with all pressurized chlorine gas piping replaced with vacuum piping. This will reduce significantly the amount of chlorine released in case of pigtail rupture.
4. The general accidental release prevention program and the specific prevention steps:
a. The general MCB Quantico Mainside Water Treatment Plant accidental release prevention program is based on the following key elements:
7 Periodic and sustained training programs for all employees
dardized preventive maintenance program
7 Use of state-of-the-art process and safety equipment
7 Use of standard operating procedures
7 Performance of hazard review of equipment and procedures
7 Implementation of an auditing and inspection program
b. Chemical-specific prevention steps include the availability of positive-pressure self-contained breathing apparatus (SCBA), which can be worn by the operators during connection/disconnection of chlorine supply, awareness of the hazardous and toxic properties of chlorine, and presence of chlorine detectors. There are chlorine "A" and "B" kits on station. Because operators are not currently trained on this equipment, their immediate actions in the event they cannot stop the flow of chlorine is to evacuate the area and notify the fire department.
c. This facility is implementing the programs required by EPA's Accidental Release Prevention Rule and with all applicable Commonwealth of Virginia codes and regulations. The MWTP has a health and
safety training program and conducts periodic review of maintenance and operating procedures.
5. Five-year accident history:
Within the past five years, there has been one injury resulting in general malaise, nausea, and irritation to the eyes, but the employee did not require evacuation. The MWTP was evacuated on two occasions as a precautionary measure when a 1-ton cylinder and a 100-pound cylinder had a leak. The fire department was called in to make repairs. The MWTP has not had in the past five years a release that meets the requirements under 40 CFR 68, Subpart B, 68.42 (a)-(c).
6. The emergency response program:
a. The facility has an emergency response program that has been coordinated with the Prince William County (PWC) Local Emergency Planning Committee (LEPC) Chairman and the Prince William County Deputy Coordinator for Emergency Services in a site visit in 1996. This program includes an emergency response training activity and notification plan which is exercised annu
ally during OPA 90 spill prevention and response training for base personnel who receive, store, and issue hazardous substances. The Chairman, PWC LEPC was an integral part of the 1998 tabletop exercise (TTX) conducted on base along with Commonwealth and Federal officials. MCB Quantico has in place mutual aid agreements with the neighboring jurisdictions.
b. The Standard Operating Procedure for employees at the Mainside Water Treatment Plan in the event of a chlorine spill is to evacuate the area if the spill cannot be contained. The fire department is notified and they are capable of responding to chlorine releases if they are outdoors. They do not have the personal protective equipment to address a chlorine release inside the buildings. MCB Quantico has access to the Commonwealth of Virginia Regional Response Teams run by the Department of Emergency Services with units responding from nearby jurisdictions in Fredericksburg and Alexandria. The base also has an arrangement with privat
e contractors in Fredericksburg and Possum Point for response and cleanup. Emergency response drills and exercises are conducted periodically on base and emergency operations and response procedures reviewed at that time. These drills and exercises are usually tied in with the public and a mini-TTX is conducted specifically focusing on working with the public and the media.
7. Planned changes to improve safety:
a. This site was constructed in 1918 and is in compliance with the NFPA regulations. There are currently no facility maintenance or upgrade projects which effect the chorline storage, handling or application processes now or in the foreseeable future.
b. The most recent changes includes the upgrade of the chlorine regulator system which involves the automatic switchover when the duty tank is empty and the stand-by tank comes on line. This precludes operators from having to switch out tanks and insures a continuous feed of chlorine.
United States Marine Corps
Marine Corps Base Quantico
Quantico, VA 22134-5001
Program Level 2 & 3 Processes
To the best of the undersigned's knowledge, information, and belief formed after reasonable inquiry, the information submitted is true, accurate, and complete.
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