Sun Metro LNG/LCNG Fueling Station - Executive Summary
The City of El Paso Mass Transit Department (Sun Metro) has been publicly owned and operated since 1977, when the City of El Paso purchased three private bus companies and created a public transit department. Sun Metro currently functions as a city department and the El Paso City Council acts as the board of directors (Mass Transit Board). It's facilities include a Liquified Natural Gas (LNG) and a Liquified Compressed Natural Gas (LCNG) vehicle fueling station (together known as the Sun Metro LNG/LCNG Fueling Station). The primary purpose of the facility is to dispense liquified and compressed natural gas (methane) in a liquified and compressed form to City of El Paso public transportation vehicles and its service fleet. |
Section 112(r) of the Clean Air Act applies to Sun Metro since the facility handles and stores methane, a flammable gas, in excess of threshold quantities. Two requirements of this section apply specifically to operations at the fueling terminal:
1. '112(r)(1) -
Purpose and General Duty Clause - The essence of the general duty clause is that an owner/operator that stores and uses hazardous chemicals in any quantity has a fundamental obligation to ensure safe operations and to have plans in place in the event of an accident to appropriately manage the situation. Sun Metro is committed to ensuring the safe operation of the LNG/LCNG Fueling Station, as well as all of its other operations, to ensure a safe workplace for our employees and a safe location for our neighbors in the community. Sun Metro, therefore, has procedures in place to prevent accidents and is committed to emergency preparedness both for the Sun Metro LNG/LCNG Fueling Station and community-wide by coordinating with the El Paso County Local Emergency Planning Commission (LEPC).
2. Risk Management Program (RMP) - The Sun Metro LNG/LCNG Fueling Station handles and stores methane in excess of 10,000 pounds, the threshold specified in '112(r). Even prior to the promulgation of '11
2(r), Sun Metro management has been very aware of the potential hazards posed by the handling and storage of flammable substances per consultant's work from design to implementation of the Alternative Fuel Station. Programs have been established to prevent accidental releases and to train personnel for emergency evacuation procedures in the event of a release. These programs are documented and described in this RMP Plan.
In accordance with the RMP definition for a "process", the Sun Metro LNG/LCNG Fueling Station is defined as one process consisting of two fueling stations as follows:
(1) Fueling Station #1 - Consists of one vertical 20,000-gallon tank and two horizontal 500-gallon tanks that store and dispense Liquified Natural Gas (LNG); and three horizontal 28.2 cubic foot (211-gallon) tanks, that store and dispense Liquified Compressed Natural Gas (LCNG). The LNG tanks are interconnected and located within the same diked area.
(2) Fueling Station #2 - Consists of two verti
cal 20,000-gallon tanks and four horizontal 500-gallon tanks that store and dispense LNG. These six tanks are also interconnected and located within the same diked area. Since the Fueling Stations are in close proximity, a release from one station involving a fire and/or explosion, whether considering a worst-case or alternative release scenario, could potentially impact the neighboring fueling station; therefore, the two fueling stations are considered as one process. Also included in this process are the associated equipment such as piping, pumps, compressors, and fuel dispensers.
For planning purposes, Sun Metro has considered the impact of a "worst case" accident, defined to be a catastrophic release of 20,000 gallons of LNG from a bulk storage tank, the largest quantity in a single vessel. It is assumed the entire quantity instantaneously forms a vapor cloud, finds an ignition source, and explodes.
Using the National Oceanic and Atmospheric Administration's (NOAA's) RMP*Comp
methodology, a potential radius of impact due to the explosion was calculated to extend to 0.3 miles. Demographic information based on the 1990 census indicates that 1,436 people distributed among 458 households live within this radius, not to mention affected areas south of the International U.S.-Mexico Border. The facility is located in the downtown area and public receptors within the radius of impact include residences, schools, recreation areas, major office and commercial areas (e.g., City, State, and Federal buildings) and railroad yards. Although not specifically denoted by the Environmental Protection Agency's (EPA's) RMP guidance as an environmental receptor, the Rio Grande is located within the worst case scenario radius of impact. No other environmental receptors are known to be located within this radius of impact. It should be noted that the worst case scenario evaluated did not include concerns within the radius of impact for the potential of co-mingling of materia
ls that might be stored in the adjacent railroad yards. Rail tanker cars have been known to be stored near the Sun Metro facility for extended periods of time in the past; however, rail cars typically switch daily and could not be reasonably evaluated.
The probability of the worst-case catastrophic event evaluated in this report is extremely remote - far less than natural catastrophes such as tornadoes and floods that could produce much more severe and extensive damage and injury. A consideration of the 0.3-mile radius has been incorporated into Sun Metro's notification and emergency response planning.
Sun Metro also considered the impact of a more likely release. This alternative release is characterized as an accident involving a transfer hose failure during unloading from an 11,000-gallon (maximum quantity) delivery truck, resulting in a release of LNG. The delivery truck and transfer hose are located outside the diked area surrounding the tanks, therefore, the release is no
t mitigated by a dike. Using EPA's April 1999 version of the Risk Management Program Guidance for Offsite Consequence Analysis (RMP Guidance for OCA) and NOAA's RMP*Comp program, the release rate was estimated to be 5,860 pounds per minute and was assumed to result in a pool fire with a potential impact distance of 0.1 mile to the heat radiation endpoint (5 kilowatts/square meter). Public receptors within this radius of impact include an office building and maintenance facility (both Sun Metro's) and adjacent railroad yards.
Sun Metro has implemented safety precautions and procedures at the Sun Metro LNG/LCNG Fueling Station designed to prevent and mitigate catastrophic releases. The Sun Metro LNG/LCNG Fueling Station has active operating, maintenance, training, and inspection procedures. In addition, Sun Metro has coordinated with local emergency responders including the El Paso Fire Department and the El Paso County Local Emergency Planning Committee. It is considered noteworth
y to mention that the Rio Grande is located just south of Sun Metro's LNG/LCNG Fueling Station. Due to the proximity along the Mexico-U.S. International Boundary, Sun Metro will also notify the sister city, Ciudad Juarez, in Chihuahua, Mexico, as necessary in the event of an environmental release.
Sun Metro's management is committed to the following:
* Preventing accidents;
* Training their employees in correct procedures in the event of an accident;
* Participating in community emergency preparedness;
* Addressing any citizen concerns by fully explaining potential hazards associated with Sun Metro operations and all steps being taken to prevent and mitigate accidents; and
* Being a good civic citizen of El Paso County and the Border Area.
With these objectives in mind, this RMP Plan has been developed to provide information about Sun Metro's management of the risks associated with the Sun Metro LNG/LCNG Fueling Station. Most important, Sun Metro stresses its commitment to ensurin
g a safe operation for its employees, its visitors, and the local community.
In addition to the above Clean Air Act requirements, the Sun Metro LNG/LCNG Fueling Station is in compliance with EPCRA and Railroad Commission of Texas requirements. Additionally, Sun Metro has taken steps to ensure safe operation at the facility including the following:
* the installation of methane detectors (with audible alarms) on the canopy around the tanks, and oxygen sensors in the containment area;
* the availability of two 125-pound extinguishers on wheels, one for each fueling station island; and
* regularly scheduled preventative maintenance.