Risk and consequence analyses of hazardous chemicals in marshalling yards and warehouses at Ikonio/Piraeus harbour, Greece

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1 Journal of Loss Prevention in the Process Industries 15 (22) Risk and consequence analyses of hazardous chemicals in marshalling yards and warehouses at Ikonio/Piraeus harbour, Greece Fotis Rigas, Spyros Sklavounos National Technical University of Athens, Department of Chemical Engineering, 157 Athens, Greece Abstract The risk and the consequences of possible accidents at Ikonio (Piraeus harbour, Greece) are investigated and analyzed in this paper. At this harbour large cargoes of dangerous chemicals (toxic or flammable) are unloaded and stored in warehouses or in marshalling yards. Houses and a school are located near the plant and are directly exposed to danger in the case of an accident. The results were obtained by Breeze Hazard Professional software package, which contains several models for performing consequence modeling through quantitative risk assessment. 22 Elsevier Science Ltd. All rights reserved. Keywords: Risk analysis; Consequence assessment; Hazardous chemicals; Marshalling yards; Chemical warehouses 1. Introduction Huge quantities of dangerous chemicals are handled and kept for intermediate temporary storage in docks, marshalling yards and port areas for further transport. Some goods are present for years in these sites, due to enterprising problems (usually financial difficulties of claiming companies) or forever (bankruptcies). Thus, many incidents have occurred in chemical storage sites during the past few years with considerable consequences to neighboring populations (Drogaris, 1993; Christou, 1999). As a result, a large number of studies have been carried out to assess the level of risk and the probable impact to the surroundings for certain port areas (Egidi, Foraboschi, Spadoni, & Amendola, 1995; Hubert & Pages, 1989; Deaves, Gilham, Mitchell, Woodburn, & Shepherd, 21; Rao & Raghavan, 1996). In Piraeus harbour and Ikonio, its main goods depot, numerous hazardous chemicals are stored near inhabited areas, totaling a 4.5 million people conglomeration of the now connected cities of Piraeus and Athens. The industrial and commercial activities in the area heavily pollute the environment, at the same time jeopardizing Corresponding author. Fax: address: rigasf@central.ntua.gr (F. Rigas). the adjacent population in the case of a major accident. Above all, the storage area of the Piraeus Harbour Organization (PHO) is in close proximity with an inhabited zone in Ikonio, where schools and other youth activities are found. Great attention has recently been focused on prediction and estimation of risk and possible damage at dangerous installations. For this purpose, accident prevention strategies have been developed that reduce the possibility of an accidental event followed by undesirable consequences. Thus, many studies have been published aiming at hazard assessment through the quantitative risk analysis (Papazoglou, Christou, Nivoliantou, & Aneziris, 1992; Khan & Abbasi, 1997; Nivolianitou, 1998; Khan & Abbasi, 1999). By its nature, any plant, in which dangerous chemicals are treated (storage/transportation), carries the probability of an accident and gives rise to the laying out of accident scenarios. In this work, four probable scenarios were analyzed engaging hazardous substances usually present in the PHO s storage area at their maximal quantities. These scenarios are ethylene oxide release and dispersion, ethylene oxide fireball, ethylene oxide vapour cloud explosion and release of toxic substances during combustion of an organophosphorous pesticide. The thermal/toxic compound doses were first computed. Then, these values were used to obtain approxi /2/$ - see front matter 22 Elsevier Science Ltd. All rights reserved. PII: S95-423(2)3-X

2 532 F. Rigas, S. Sklavounos / Journal of Loss Prevention in the Process Industries 15 (22) Nomenclature I S t P IDLH LC 5 LD 5 specific impulse as a function of overpressure P S and positive phase duration expressed by the integration: i s P S (t)dt t P immediately dangerous to life and health concentration limit for toxic gaseous compound or vapours. These levels have been established by NIOSH as the concentrations from which one could escape within 3 min without any escape-impairing symptoms or any irreversible health effects lethal concentration 5%: a concentration by which 5% of the exposed population will be fatally injured for a particular time of exposure. lethal dose 5%: a dose value by which 5% of the exposed population will be fatally injured. positive phase duration a particular time in which overpressure decreases to zero after increasing and taking the maximum value by a shock or pressure wave RD radiation dose: function of heat radiation intensity (q) and time of exposure (t) given by the equation RD t q 4/3 TD total dose: function of concentration (C) and exposure duration (t t ) given by the integration: t TD Cdt t Tox.C toxic concentration: lowest measured concentration by which a degree of toxic effect is still possible for a particular time of exposure. Tox.D toxic dose: the lowest dose value by which a degree of toxic effect is still possible. Toxic endpoint The threshold concentration value for serious injury from exposure to a toxic substance in the air. mate percentages of injured people out of the totally affected population due to the accidental events. The types of damage investigated were burns of various degrees, acute poisoning, or even death. The response/dose correlations were expressed by probit functions (Green Book, 1989). The toxicity data given in the latter report for many chemicals and derived from lab animal experimentation, lead to total dose calculations and to poisoning or lethal effect estimations for a defined percentage of the affected population. 2. Types of accident investigated Generally, the types of accident that may take place are: fire, explosion, release and dispersion of toxic gases/vapors or a combination of these. The types of accident considered in the scenarios of this study are analyzed below Bleve Bleve (boiling liquid expanding vapour explosion) is a phenomenon resulting from the failure of a vessel containing a liquid at a temperature significantly above its boiling point at normal atmospheric pressure. The main hazard posed by Bleve (Yellow Book, 1997) of a container filled with a flammable volatile liquid is a fireball and the resulting radiation, due to instantaneous ignition of the flammable vapour cloud. The initiator for this ignition could be a hot source (e.g. the hot point of a motor), a spark of electrostatic origin, friction or a thermal source Unconfined vapour cloud explosion (UVCE) This type of explosion (American Institute for Chemical Engineers, 1994) takes place when a sufficient amount of flammable material (gas or liquid having high vapor pressure) is released and mixed with air to form a flammable cloud, such that the average concentration of the compound in the cloud is higher than the lower limit of explosion. The explosion occurs in an open space and the resulting overpressure affects humans and buildings through a blastwave covering large distances Pool fire The continuous release of a flammable liquid usually results in a pool fire. When the liquid is spilled in a confined space (e.g. in a warehouse), the pool size is also confined and the amount of air that sustains the fire

3 F. Rigas, S. Sklavounos / Journal of Loss Prevention in the Process Industries 15 (22) is limited, because the ventilation is controlled by the ventducts (Atkinson & Jagger, 1994). In this case the type of the fire is characterized as confined. When the liquid is spilled in an open area, it covers a large surface area and the amount of air is unlimited. Then the fire is referred to as unconfined Release and dispersion of toxic gases and vapors During the combustion of a flammable material a lot of chemical compounds are produced and travel large distances downwind, forming a combustion gas cloud. Some of them (CO, NO x ) are toxic and even fatal to humans at sufficiently high doses. Moreover, the fraction of toxic material surviving fire is 1.5 1%. In the absence of more accurate estimations, one can assume that particulate matter absorbs approximately 5% of the kinetic energy of the combustion gaseous products. In this way the particles are carried away by these gases traveling some distance into the heavy gas cloud and affect inhabitants before they meet the ground. Thus, the curve, which represents the change of particulate concentration with time at a specific point, is similar to that for gaseous combustion products. 3. Computational tools The software mainly used in this work was BREEZE HAZ PRO developed by Trinity Consultants, which is a fully integrated family of consequence models for performing offsite consequence modelling and emergency response planning through quantitative risk assessment. There are in total 12 models in this package: EXPERT, DEGADIS, SLAB, AFTOX, INPUFF (all used to model gas releases), JET FLAME, CONFINED POOL FIRE, UNCONFINED POOL FIRE, BLEVE (all used to calculate the thermal radiation flux levels at various specified distances in case of blaze), TNT EQUIVALENCY EXPLOSION, TNO MULTI-ENERGY EXPLOSION and BAKER STREHLOW EXPLOSION (all used to calculate the overpressure levels at specified distances in the case of explosion). The models used in this task are described below EXPERT model The EXPERT model determines the key model input parameters based on user specified physical process information, chemical property data, storage and ambient conditions. It is integrated with each dispersion model to simplify the process of source term analysis and consequences modeling. EXPERT estimates the gas state of a release entering the atmosphere. It calculates release duration, exit velocity and pressure and density in addition to emission rate of the gas or aerosol injection into the atmosphere SLAB model The SLAB computer model simulates the dispersion of denser-than air releases. The types of releases treated by this model include ground level evaporating pool, an instantaneous volume source, a stack (or generally elevated vertical jet) and an elevated horizontal jet DEGADIS+ model DEGADIS+ is a chemical-specific model that predicts dispersion from instantaneous, steady state or transient releases of dense gases. This powerful model is useful for determining toxic gas concentrations of episodic releases from single sources over flat terrain and at particular meteorological conditions for the duration of the release BLEVE model The BLEVE model estimates the parameters associated with a fireball phenomenon, which usually follows a BLEVE event or generally a sudden release of a flammable gas. In addition to fireball diameter and duration, this model calculates the thermal dose, which affects thermal radiation receptors at specified distances (points of interest) TNO MULTI-ENERGY and TNT EQUIVALENCY EXPLOSION models The TNO MULTI-ENERGY EXPLOSION model calculates the distance to various overpressure levels specified by the user for an unconfined vapour cloud explosion. It takes into account the variability of the blast strength by expressing the explosion as a number of fuel air charges, each with individual characteristics. By modeling the vapour cloud explosion as the number of smaller blasts in each centre on confined sections of the cloud, this model is appropriate for estimating nearfield damage. The TNT EQUIVALENCY EXPLOSION model calculates the distance to various over-pressure levels specified by the user for an unconfined vapor cloud explosion. It uses a proportional relationship between the flammable mass in the cloud and an equivalent weight of TNT. It is assumed that the entire flammable mass is involved in the explosion and that the explosion is centered at a single location. The TNT equivalency method is simple and tends to be better for estimating far-field damage. Both these models are able to calculate the overpressure developing at specified distances (points of interest).

4 534 F. Rigas, S. Sklavounos / Journal of Loss Prevention in the Process Industries 15 (22) Risk analysis and impact assessment 4.1. Methodology Risk analysis deals with the hazard spotting of dangerous chemicals and constitutes the first step in impact evaluation and preventive measures establishment. The methodology followed in this study was: 1. Identification of hazards and high risk points in the installations in addition to possible affected points. 2. Consideration of suitable accident scenarios and simulation of the resulting accidents (use of the appropriate model involved in Breeze HAZ PRO software package). 3. Estimation of the impact that the accidents may have (use of steps (1) and (2)). Regarding the hazard identification, the points of interest in the plant are shown in Fig. 1, while the algorithm including the above steps is presented in Fig Input data Among the dangerous chemicals frequently unloaded in the docks of PHO at Ikonio are ethylene oxide (maximal quantity per batch: 1 kg) and the pesticide Azinphos-methyl (maximal quantity per batch: 1 kg). The former is highly flammable and the latter pro- Fig. 2. Algorithm of risk and consequence assessment. Fig. 1. Aerial photo of Ikonio area. Installation limits, blocks and the school are presented. nos. 1 and 2: warehouses; no. 3: school; nos. 4 and 5: blocks; no. 6: street.

5 F. Rigas, S. Sklavounos / Journal of Loss Prevention in the Process Industries 15 (22) duces toxic gaseous products when burning (Smith- Hansen & Jorgensen, 1994). Both of them are toxic and they can even cause death in humans at certain doses. The fact that the area around the installation is inhabited gives a particular interest to the evaluation of the consequences in the case of an accident. More specifically, next to the storage area many houses are located (Fig. 1, blocks no. 4 and no. 5), as well as a public school (Fig. 1, no. 3). In the same figure, no. 1 and no. 2 represent the warehouses of the installation and no. 6 the street that connects Ikonio with Piraeus. The scale (1/1) and the North direction are also shown in Fig. 1. Many containers are also yarded outside warehouses no. 1 and no. 2. Ethylene oxide is usually stored in warehouse 1 or outside, while Azinphos-methyl containers are stored in warehouse 2. Analysis of the subsequent accident scenarios aims chiefly at the prediction of the effects on students (school, no. 3) and on residents (blocks no. 4 and no. 5). Moreover, a dispersion model demands a value of the wind speed in order to run. Therefore, related statistical data for the Piraeus area were obtained from the Hellenic National Meteorological Service. With reference to these data, an average value of wind speed in the months of April and May (see Section 4.3) is 1.8 m/s. In addition, a typical value of relative humidity of the air is required. Through the same data, the average value was calculated to be equal to 62.5% Prevailing winds The continuous change of wind direction during a day requires the use of meteorological data in order to ascertain the major winds that blow in the greater area of Ikonio. In the case of a toxic gas release, the wind favors the movement of the toxic cloud onto the school and the surrounding blocks when it is moving in a Southeast or South direction. Analytically, with regard to gas release in a Southeast wind (direction 1 11 ), the cloud will affect the school (no. 3) and the nearest to the school houses in the same direction (no. 4). In the case of a South wind (direction ), the cloud will affect the areas nearest to the warehouse block (no. 5). Warehouse no. 1 is 71 m away from block no. 5, 8 m from the school and 3 m from block no. 4. Warehouse no. 2 is 182 m away from block no. 5, 133 m from the school and 31 m from block no. 4. The information given by the obtained data shows that the South wind prevails in the months of April, May and June, while a Southeast wind blows mainly in April and May. All the other monthly frequencies of the South wind are moderate to low and for the Southeast wind they are low. Table 1 Results obtained via the EXPERT source term model Result Emission rate Exit velocity Used release duration Vapor fraction Exit pressure Value kg/s 9.37 m/s s 5.86E kpa 5. Illustration of accident scenarios and consequence estimation 5.1. Scenario 1: ethylene oxide dispersion Southeast wind In this scenario an amount of 1 kg of ethylene oxide is assumed to be released into the atmosphere as a horizontal jet after the fall and rupture of the container in which the ethylene oxide is stored under pressure. The resulting ethylene oxide cloud will travel a long distance until fully mixed with the air by the wind and will cover the school when the wind has a Southeast direction. The appropriate model for this type of release is SLAB, which requires the emission rate of the substance. The EXPERT model can calculate this parameter. Thus, for a hole diameter equal to.5 m, the EXPERt model gives the results found in Table 1. These results are automatically transferred to the SLAB model, which gives the final results regarding the change of ethylene oxide concentration with time at a specified point. Furthermore, isorisk curves and covered areas are shown in Fig. 3. With regard to the school and block no. 4 this variation is described in Fig. 4. Then, by using the EXCEL program, it is possible for the total dose (TD) to be calculated via the equation: t TD t Cdt where C is the concentration of dispersed compound, t is the time the cloud starts to pass above a particular point, t is the time it takes for the cloud to entirely pass above that particular point (t t). The TD for each point was calculated by integration of the corresponding curve (Fig. 4): TD s Cdt C 1 dt C 2 dt C 3 dt 145 (g s)/m TD 4 Cdt C 1 dt C 2 dt 9.9 (g s)/m

6 536 F. Rigas, S. Sklavounos / Journal of Loss Prevention in the Process Industries 15 (22) Fig. 3. Isorisk curves representing the concentrations: toxic end point (9 mg/m 3 ) outer white contour; IDLH (146 mg/m 3 ) middle black contour; LFL (54 17 mg/m 3 ) inner white contour. Snapshot at 6 s elapsed time with Southeast wind South wind The areas nearest to the warehouse block (no. 5) will be affected by a South wind. In this case, the change of ethylene oxide concentration with time at this point during the cloud travel is shown in Fig. 4. Furthermore, isorisk curves and covered areas are shown in Fig. 5. The TD 5 is then calculated with the integral: TD 5 Cdt C 1 dt C 2 dt C 3 dt 125 (g s)/m Fig. 4. Change of ethylene oxide concentration with time at points of interest. The LD 5 value for ethylene oxide is 1238 (g s)/m 3 which is higher than the value of TD s calculated. On the other hand the toxic dose (Tox.D) is equal to Tox.D=18 (g s)/m 3 which is less than the TD s value calculated above. As a result, it can be inferred that the ethylene oxide cloud will not affect students fatally, but they will appear to have symptoms such as dizziness, nausea, difficulty in breathing and vomiting (Sax, 1957). Moreover, TD 4 Tox.D, which means that block no. 4 is beyond the dangerous zone. Comparing again the TD 5 value with Tox.D and LD 5 values, it is apparent that Tox.D TD 5 LD 5. Namely, there will be poisoning symptoms as previously Scenario 2: ethylene oxide fireball Due to the high exit velocity and brief release time (Table 1) of ethylene oxide from the vessel, its concentration immediately after the entire amount has been released is above the lower flammability limit (Figs. 3 and 5, inner contour). As a result, the formed cloud will turn into a fireball when meeting an ignition source. The

7 F. Rigas, S. Sklavounos / Journal of Loss Prevention in the Process Industries 15 (22) Fig. 5. Isorisk curves and impact area for South wind. The contours represent the same as Fig. 2 values of ethylene oxide concentration. appropriate simulation model for this phenomenon is BLEVE, which can estimate the radiation levels and thermal doses for the amount of ethylene oxide (1 kg). The diameter of the fireball provided by the model is equal to 58 m and its duration is equal to 4.5 s. The affected area is presented in Fig. 6 and the results regarding radiation doses at several distances are shown in Table 2. From this table one can see that block no. 4 is not endangered. The radiation dose at this distance is too low to cause burns even of the first degree. The pedestrians walking along the avenue (no. 6) at the time of the accident will be surely fatally injured because of the excess thermal intensity (Table 2). At block no. 5 the value of thermal radiation dose corresponds to 6% probability for third degree burns, 2% for second degree burns and 74% for first degree burns. At the school area (no. 3), the probabilities of injury due to thermal radiation are 2% for third degree, 5% for second degree and 93% for first degree burns. Eventually, the thermal radiation will be perceptible over 1 km away from the point of the accident Scenario 3: ethylene oxide vapour cloud explosion (VCE) This type of accident has been simulated by the multienergy explosion model. Three levels of overpressure were given as input data, namely, 3 kpa (upper contour), 51 kpa (middle contour) and 3.5 kpa (lower contour). The first value of overpressure is fatal, the second one results in a 5% probability of fatal injury due to collision of the victim with a stable surface and the third value sets an overpressure level tolerated by humans (see Fig. 7). To estimate the overpressure levels at point nos. 3, 4, 5 and 6 where overpressure will affect points 3, 4, 5, 6 almost simultaneously, the corresponding distances were logged as input data and the programme calculated the overpressure values in addition to positive phase duration at these points (Table 3). The results gave rise to the following conclusions. With regard to the avenue (no. 6), there is a 15% probability of fatal collision of a victim with a stable surface and a 5% probability of eardrum rupture. Moreover, taking into account that even loaded train carriages turn over just at 51 kpa overpressure, passing cars will turn over. Regarding block no. 5 and the school no. 3 the effects will be similar. A percentage of about 5 75% of all outer walls will be lightly to heavily damaged. The damage will not be repairable because most of the houses in the area are old. For those found in one of these houses or in the school building, there is a 5 8% probability of injury and a 2 5% probability of being fatally squashed by the crumbling walls. As far as block no. 4 is concerned, minor damage is expected, such as breakage of windowpanes. Furthermore, damage to buildings

8 538 F. Rigas, S. Sklavounos / Journal of Loss Prevention in the Process Industries 15 (22) Fig. 6. Radiation levels for an ethylene oxide fireball incident, representing the values: 12 kw/m 2 (fatal burns) inner white contour; 5 kw/m 2 (probability of death 34%, probability of second degree burns effect 46%, probability of effect of first degree burns 2%) middle black contour; and 11 kw/m 2 (tolerated by humans for 4.5 s duration of fireball) outer white contour. Table 2 Radiation doses at points of interest for the BLEVE model Specified distance (m) Radiation intensity (kw/m 2 ) Radiation dose [s(w/m 2 ) 4/3 ] fireball duration 4.5 s 45 (no. 6) (no. 5) (no. 3) (no. 4) (e.g. roofs, window panes) is possible, even at 1 kpa overpressure. The TNT equivalency model (appropriate for estimating the long distance consequences) computed that this overpressure would be developed at a 955 m distance. Consequently, the blast wave will affect not only the nearby buildings, but also buildings in the distance where densely populated areas are found Scenario 4: dispersion of toxic substances yielded during the combustion of the pesticide Azinphosmethyl In this scenario a batch of 1 kg of the pesticide Azinphos-methyl is assumed to catch fire as it is stored in warehouse no. 2. A typical burning rate for material on fire in an enclosed space is.8 kg/m 2 s. When the liquid is spilled, it is assumed to be the area of the warehouse no. 2 (52 m 2 ). For an average time of 12 s, a quantity of approximately 5 tons of the pesticide would have burned. Assuming perfect combustion, the main combustion products would be CO 2 and NO 2, which would travel into the atmosphere forming a toxic cloud after their emission The dispersion of NO 2 toxic compound was first estimated The appropriate model to simulate the assumed vertical dispersion of NO 2 is Degadis. The isorisk curves for a Southeast and a South wind are shown in Figs. 8 and

9 F. Rigas, S. Sklavounos / Journal of Loss Prevention in the Process Industries 15 (22) Fig. 7. Isorisk curves showing the impact area and representing the following overpressure values: 3 kpa (severe risk inner white contour); 51 kpa (high risk middle black contour) and 3.5 kpa (moderate risk outer white contour). Table 3 Calculated overpressures at specified distances for the vapour cloud explosion Distance (m) Overpressure (kpa) Positive duration (s) I S (Pa s) Damage to structures 45 (no. 6) Cars turned over 7 (no. 5) % of walls destroyed or unsafe 8 (no. 3) Threshold for partial demolition 3 (no. 4) Threshold for minor damage 9, respectively. The change of NO 2 concentration with time at points 3, 4 and 5 is shown in Fig. 1. The total doses at these points were calculated with the integral: Point 3: TD 3 C dt C 1 dt 71ppm ( )s C 3 dt 837,36 ppm s 13 where 71 ppm is the average NO 2 concentration above the school during the time period s, in which the concentration is approximately stable Point 4: TD 4 C dt C 1 dt 31ppm ( )s C 3 dt 379,7 ppm s 1411 where 31 ppm is the average NO 2 concentration as previously Point 5: TD 5 C dt C 1 dt 538ppm ( )s C 3 dt 623,3 ppm s 128 where 538 ppm is the average NO 2 concentration as previously. The comparison between TD i values (i 1, 2, 3) and LD 5 283,5 ppm s leads us to con-

10 54 F. Rigas, S. Sklavounos / Journal of Loss Prevention in the Process Industries 15 (22) Fig. 8. Isorisk curves showing the travel of dispersed NO 2 as a cloud for Southeast wind. The cloud is passing above the school (no. 3) and block (no. 4). Outer white contour: 5 ppm; middle black contour: 215 ppm; inner white contour: 5 ppm. clude that NO 2 doses will be lethal at all points 3, 4 and 5 for a higher percentage than 5% of the totally affected population Vapor droplets or particles of the burning liquid would be carried away by the gaseous products of combustion It is assumed that the curve of Azinphos-methyl vapors follows the curve of CO 2 during the cloud travel at a proportion of 1%. As a result one can simulate the dispersion of CO 2 with a gas dispersion model and assume the Azinphos-methyl concentration to be equal to 1% of the CO 2 concentration. The isorisk curves given by the Degadis model are presented in Figs. 11 and 12, while the change of Azinphos-methyl concentration with time at points of interest is shown in Fig. 13. The total Azinphos-Methyl doses at points 3, 4 and 5 were calculated with the integral: Point 3: TD 3 C dt C 1 dt mg/m 3 (13 26)s C 3 dt (g s)/m 3 where 269 mg/m 3 is the average Azinphos-methyl concentration above the school during the time period s Point 4: TD 4 Cdt C 1 dt mg/m 3 (138 36)s C 3 dt (g s)/m 3 where mg/m 3 is the average Azinphos-methyl concentration as previously Point 5: TD 5 Cdt C 1 dt mg/m 3 (13 28)s C 3 dt (g s)/m 3

11 F. Rigas, S. Sklavounos / Journal of Loss Prevention in the Process Industries 15 (22) Fig. 9. Isorisk curves showing the travel of dispersed NO 2 as a cloud for South wind. The cloud is passing above block no. 5 and contours represent the same as Fig. 6 values of NO 2 concentration. 6. Conclusions This risk analysis and impact assessment applied for four accident scenarios that may occur at Ikonio marshalling yard close to Piraeus harbour resulted in the following conclusions: Fig. 1. Change of NO 2 concentration with time at points of interest. where 222 mg/m 3 is the average concentration as previously. The LD 5 for Azinphos-methyl is equal to: LD 5 45 (g s)/m 3. Comparing the LD 5 value with TD i, one can easily conclude that a percentage greater than 5% of the totally influenced people would be fatally affected. The results of consequence analysis for the scenarios considered are shown in Table 4 whereas their lethality effects are shown in Table 5. The toxic gas dispersion (scenarios 1 and 4) would acutely affect the pupils of the nearby school and local inhabitants. The consequences would be poisoning (symptoms such as nausea, vomiting, coughing and pulmonary diseases, probably long lasting) or even fatal for a large part of the affected population. A fireball event (scenario 2), emitting high amounts of thermal radiation, would cause burns to humans at a distance less than 132 m. The pupils of the nearby school and inhabitants would be endangered in this case. In the event of a vapor cloud explosion (scenario 3) the blast wave would cause fatal consequences to the nearby population. Moreover, it would induce damage to houses within a radius of approximately 1 km. Generally, the distances between warehouses 1, 2 and the residential blocks or the school are too short. This is the reason for the school area and the surrounding

12 542 F. Rigas, S. Sklavounos / Journal of Loss Prevention in the Process Industries 15 (22) Fig. 11. Isorisk curve representing the LC 5 value (25 mg/m 3 ) for Azinphos-methyl and showing the travel of its droplets in the Southeast wind. Fig. 12. Isorisk curve representing the LC 5 value (25 mg/m 3 ) for Azinphos-methyl and showing the travel of its droplets in the South wind.

13 F. Rigas, S. Sklavounos / Journal of Loss Prevention in the Process Industries 15 (22) Table 5 Leathality effect of various scenarios at the Ikonio s installations Lethality effect of considered scenarios Points of Interest School No. 3 Block No. 4 Block No. 5 Ethylene oxide release No No No Ethylene oxide fireball No No No Ethylene oxide UVCE Yes No Yes NO 2 dispersion Yes Yes Yes Vapours dispersion Yes Yes Yes Fig. 13. Change of Azinphos-methyl vapor concentration with time at points of interest. houses being affected in a very short time, and in a way that emergency response planning could not be applied. Based on the above conclusions the following recommendations for protection measures could be deduced: Exclusion or at least reduction of the quantities of the hazardous cargoes that are unloaded and stored at the marshalling yard of Ikonio. Indoor storage of containers with hazardous materials in the warehouses. Thus, in the event of a fire, sufficient time would be given for the firemen to arrive at the site and take over, or the emergency plan for the evacuation of the inhabitants of Ikonio to be put into practice. Due to the eventuality of toxic or flammable gas release from a warehouse into the atmosphere, sufficient quantities of inert gases should be kept for the purpose of dilution of the hazardous gases to below a toxic level or to below the lower flammability limit (fireball and vapour cloud explosion avoidance). References American Institute for Chemical engineers (1994). Guidelines for evaluating the characteristics of vapor cloud explosions, flash fires and BLEVE S. New York. Atkinson, G. T., & Jagger, S. F. (1994). Assessment of hazards from warehouse fires involving toxic materials. Fire Safety Journal, 22, Christou, M. (1999). Analysis and control of major accidents from the intermediate temporary storage of dangerous substances in marshalling yards and port areas. Journal of Loss Prevention in the Process Industries, 12, Deaves, D. M., Gilham, S., Mitchell, B. H., Woodburn, P., & Shepherd, A. M. (21). Modeling of catastrophic flashing releases. Journal of Hazardous Materials, A88, Drogaris, G. (1993). Learning from major accidents involving dangerous substances. Safety Science, 16, Egidi, D., Foraboschi, F. P., Spadoni, G. E., & Amendola, A. (1995). The ARIPAR project: analysis of the major accident risks connected with industrial and transportation activities in the Ravenna area. Reliability Engineering and System Safety, 49, Green Book (1989). Methods for the determination of possible damage. Rep CPR 16E. Voorburg, The Netherlands. Hubert, P., & Pages, P. (1989). Risk management for hazardous materials transportation: a local study in Lyons. Risk Analysis, 9(4), Khan, F. I., & Abbasi, S. A. (1997). Risk analysis of an epichlorohydrin manufacturing industry using the new computer automated tool MAXCRED. Journal of Loss Prevention in the Process Industries, 1, Table 4 Results of consequence analysis for the scenarios considered at Ikonio s marshalling yards and warehouses Scenarios and damaging Points of interest Limiting values events School no. 3 Block no. 4 Block no Ethylene oxide release Acute poisoning None Acute poisoning 18 (g s)/m (g s)/m (g s)/m (g s)/m 3 2. Ethylene oxide fireball 1st, 2nd degree burns Perceptible radiation Serious injuries 11 kw/m kw/m kw/m kw/m 2 (fireball duration 4.5 s) 3. Ethylene oxide UVCE Partial demolition Minor damage Partial demolition 1 kpa 4kPa 5.6 kpa 45 kpa 4. NO 2 dispersion Fatal effect Fatal effect Fatal effect 283,5 ppm s 837,36 ppm s 379,82 ppm s 623,294 ppm s 5. Vapours dispersion Fatal effect Fatal effect Fatal effect 45 (g s)/m (g s)/m (g s)/m (g s)/m 3

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