BOS 3125 Unit III Case Study

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Risk Assessment at Local Gas Station

Columbia Southern University

Risk Assessment at Local Gas Station

The purpose of this study was to conduct a risk assessment at “Local Gas Station” to identify hazards related to fuels stored in the underground tanks, which could harm clients, employees, and the nearby community. The motivation is to suggest recommendations for preventing spills, releases, and possible explosions; and also to provide suggestions for response actions if an emergency occur.

Local Gas Station is a business that constitute a risk to the area where it is located which is highly frequented, therefore, in case of accident many people would be affected and potentially harmed. Natural hazards identified are lightning and wildfire that could affect a nearby wooded area. Some of the physical hazards found are potential fires, and explosion due to static energy that could cause sparks or due to traffic accidents involving the pumps because the gas station is located in proximity of a busy intersection. Chemical hazards determined are potential spills and releases of gasoline or diesel. Security is another issue identified due to the retail store on site which potentially attracts criminals. Potential shooting could cause fire and explosion affecting the underground tanks.

This outcome has been reached by investigating the site, conducting a walk through the gas station and the surrounded area, and by using the General Behavior Model (GEBMO) developed by Ludwig Brenner.


During the inspection at the site and at the nearby area, the following characteristics have been found. Local Gas Station is located at a busy intersection and it is surrounded by several businesses which contribute to make the area very frequented. At the front there is a large development that host an elementary school and in the back there is playground area with a baseball field and a large wooded area. This business has also a convenience store on site. The station has four pumps, all of them supplying three types of gasoline and diesel. The pumps are connected to an underground tank with a capacity of 30,000 gallons divided in three compartments, 10,000 gallons for each type of gasoline, plus and additional tank with a capacity of 10,000 gallons which store diesel.


The risk assessment has been conducted using the model developed by Ludwig Brenner called General Behavior Model (GEBMO). The first step of this model is stress which give rise to the occurrence of an event. Common stressors are: THERMAL– extreme temperature can cause intolerable expansion, contraction, weakening, or consumption of tank, pump, and its parts. May also increase internal pressure and reduce shell integrity. CHEMICAL-Uncontrolled reactions can happen if gasoline or diesel are mixed with other chemicals. MECHANICAL-physical application of energy resulting in damage to tanks or pumps (i.e.-crushing, abrading, scoring). At Local Gas Station the biggest concern is the tank with gasoline because diesel is considered combustible, not flammable.  In Florida, where Local Gas Station is located, the thermal risk identified is high temperatures during most of the year; the chemical risk is constituted by potential spills which would affect a large portion of population living in the area; and the mechanical risk existing is represented by the probability of crashes between vehicles entering or exiting the site. These crashes can involve some of the four pumps and consequently the underground tanks. As result of this potential crashes one or more pumps can receive the necessary stress to breach (step 2) and explode causing the release (step 3). At this point the engulf step (step 4) is reached and it is necessary to keep in mind all the contributory factors that could condition the release, such as topography, weather condition, amount of the release, and type of release. According to the model the dispersion can occur in different ways. At Local Gas Station, if a release arises, it likely would be as stream, pool, or irregular because the gasoline is liquid. Step 5 is contact or exposure phase. At the site studied this occurrence can be very dangerous because many people would be affected, including kids. In this area the risk has been identified most likely as immediate and short term. Someone could also be affected in medium term. A long term exposure is unlikely to happen. The harm caused (step 6) by an accident at this station has been determined as critical due to the amount of people that potentially can be affected and also due to the size of the release that in case of explosion can be very large. Toxicity of the release in this case is also another factor that has been considered during the assessment. In addition to crashes, lightning has been identified as another hazard that could trigger the GEBMO process in the same way above described.


As identified during the risk assessment, crashes against the pumps are likely to occur; therefore, in order to prevent accidents, management should consider to install protective boundaries, such as concrete columns, yellow or red in color, and at least two feet high, around each pumps so in case a vehicle crashes against the pump, it will be stopped by the columns. In alternative traffic controls devices can be installed at the entrance and exit of the site. Another suggestion to prevent spills from underground tanks is to periodically check them to promptly discover damages and to order ordinary and extraordinary maintenance as necessary. Lightning is another hazard identified. Vapor emitted during refueling and delivery operations could be ignited if hit by a lightning. In order to prevent fire and explosions originated by those vapor, management should require plastic covers to apply at each nozzle and similar protective devices to apply at the delivery pipes. Also grounding is required to reduce static energy.


In case the preventive measures adopted fail and an accident occurs it will be necessary to act promptly in order to save lives. Once a leak is confirmed, immediate response actions must be taken to minimize or eliminate the source of the release and to reduce potential harm to human health, safety, and the environment. First responses may include removing flammable or explosive materials from the release area, such as propane cylinders, and preventing spills to storm water utilities, wetlands, and surface waters. Evacuation should be ordered at least half mile around the area to avoid injuries caused by inhalation of the smoke, if a fire or explosion occur. Elementary school and nearby development have to be prioritized during the evacuation. It will be necessary to provide bottled water for all people in the area not involved in evacuation which rely on groundwater for drinking, bathing, and food preparation. The intrusion of petroleum vapors into houses and buildings in the nearby development is another important concern and may require the active ventilation of indoor building space, therefore, as immediate action it is necessary to monitor the air to evaluate the level of pollution. These are the minimum actions required in the event of a spill.


Local gas station has the same level of risk of others gas stations, but it is placed in a very busy area, therefore, a spill in this circumstances will affect many people. Sites like this have to be protected and all types of measures have to be adopted to prevent accidents. As always prevention and training are the best response to accidents.


Joel M. Haight (2012). Hazardous Material Management and Hazard Communication from The Safety Professionals Handbook, 2nd edition

Community and Environmental Defense Services. Retrieved from

HazMat for First Responders Chapter 4 – Hazard & Risk Assessment (2nd Edition). Retrieved from

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