Immediately Dangerous To Life Or Health Research Articles

Consequence modeling and analysis of ethanol leakage from storage tank using the ALOHA program

Chemical spills pose a significant threat to the safety of people living nearby, as well as to air quality and occupational safety. Therefore, preventing chemical spills has become a key issue in environmental protection and process safety. This study aims to evaluate the effects of ethanol released from a tank at a chemical plant in Istanbul, Türkiye. The Areal Location of Hazardous Atmospheres model (ALOHA) version 5.4.7 estimates the storage tank's leakage radius and spread risk under three scenarios. ALOHA can assess the area affected by chemical hazards. The model shows that if the spill occurs 10 centimeters from the base of the tank, the toxic concentration of ethanol exceeds the Immediately Dangerous to Life or Health (IDLH) threshold (i.e., 3300 parts per million) at a distance of 31 meters from the place of release. In addition, when the ethanol concentration exceeds 60% of the Lower Explosive Limit (LEL) (i.e., 19800 parts per million), the flammable vapor cloud extends up to 31 meters from the place of release. For a Boiling Liquid Expanding Vapor Explosion (BLEVE), the mass of the fireball is assumed to be 100%, resulting in the worst possible scenario. During BLEVE, it is estimated that the fireball's diameter and time duration, determined by the amount of Ethanol present, would be 141 meters and 10 seconds, respectively. The results show that the thermal radiation effects caused by Ethanol BLEVE are extremely dangerous.

Fire-resistant performance of new sustainable waste-lightened composites with glass and basalt fibres reinforcement

In recent years, numerous studies have been conducted on the incorporation of plastic wastes into gypsum or plaster compounds with the aim of achieving more sustainable and environmentally friendly materials. Despite the vulnerability of plastic materials to high temperatures, it is not common to analyze the behavior of these new compounds in case of a fire. In this study, different lightweight plaster compounds have been developed, partially replacing the original raw materials with plastic waste in dissolution up to 23.5% and reinforced with glass and basalt fibers. After exposing the compounds to real direct fire, mechanical characterization (flexural strength, compressive strength, surface hardness tests) and physicochemical characterization (XRD, TGA) have been carried out, including the calculation of CO and CO2 emissions associated with the combustion of the compounds, as well as imaging by scanning electron microscopy. The results show that the reduction in the density (between 15%−24%) of the new compounds favored lower temperatures during exposure to flames, preventing material cracking. Likewise, the new composites experienced a loss in flexural strength between 44%− 51%, and a drop in compressive strength between 2%− 63%, being these losses in strength lower than those experienced by the reference composites. The addition of glass fibers demonstrated to confer better flexural behaviour to the compounds with added waste, while the basalt fibers were more efficient in compression. Furthermore, the estimated toxic emissions produced during the combustion of the designed compounds did not exceed the immediately dangerous to life or health (IDLH) values established by the Material Safety Data Sheet (MSDS), remaining below 2000 ppm/h for CO and 40,000 ppm for CO2. This study contributes to a better understanding of the behavior of plaster compounds with incorporation of plastic waste in case of fire, highlighting the developed materials as a viable alternative for the production of more environmentally friendly prefabricated products.

Data-driven modeling of downwind toxic gas dispersion in lithium-ion battery failures using computational fluid dynamics

Understanding the toxicity hazard associated with lithium-ion battery systems (electric vehicles, e-mobility devices, energy storage systems, etc.) is critical due to their increasing prevalence in densely populated areas. In this work, a meta-analysis of literature data on the main toxic gas species emitted by lithium-ion batteries was conducted. The aggregated data were used as inputs to computational fluid dynamics simulations to characterize the universe of potential toxic gas concentration profiles. These simulations were run for various ambient conditions and battery characteristics. Results are reported in terms of estimated minimum safety distances based on immediately dangerous to life or health (IDLH) values, which could help inform decisions regarding effective firefighting and evacuation recommendations. A sensitivity analysis was also run to identify the key factors that influence safety distances as well as the combination of factors that led to the largest and shortest safety distances. Additionally, using toxicity data from the literature, the downwind toxicity of an internal combustion engine vehicle fire was compared to that of an electric vehicle fire. A relatively simple simulation setup was used for all simulations to make the results as general as possible.

An optical nose based on array of metal-doped carbon dots for identification of hazardous amines and assessing meat freshness

There is an obvious pressing demand for the sensitive and rapid, identification of toxic gases as environmental concerns. In this study, a facile approach for the detection and identification of amine solvents is reported. A colorimetric sensor array composed of different ninhydrin-mediated transition metal-doped carbon dots (TMCDs), deposited on a paper substrate, could sniff the odor of 29 different amines and accomplish their accurate identification. This analytical device generates a unique response pattern for each amine. Modeling the response data of the sensor array by linear discriminate analysis yields a discrimination accuracy of 94 % for the amines. Also, this method allows rapid quantification of ethylamine and isopropylamine in the concentration ranges of 0.008–1600 ppm and 0.05–828 ppm with detection limits of 1.4 ppb and 39 ppb, respectively, which are well below the immediately dangerous to life or health (IDLH) limit concentration for these amines. Interestingly, this sensor array provides discrimination between the isomers of some amines. Moreover, binary and ternary mixtures of amine solvents could be well recognized with this sensor. The application of the sensor array was tested for the assessment of the quality and freshness of some kinds of meat.

Intra-workday fluctuations of airborne contaminant concentration and the time-weighted average

Air contaminant concentrations vary between and within workdays and are often measured across a workday by passing a known air volume through a collection device. Laboratory analysis determines the contaminant mass trapped, providing a time-weighted average air concentration (C TWA). This approach was driven by the best technologies available as exposure measurement processes developed and accuracy and measurement precision were sought. However, all integrated concentration•time (C•t) values determining C TWA are equally weighted in assessing exposures, intra-workday concentration variability is unknown, and results are available days later. At times inappropriately, an occupational exposure limit (OEL) expressed as a C TWA also requires equal weighting of all C•t values across an exposure period following concepts of Haber’s law. Continuous monitoring (real-time detection) informs both the C TWA and the variability of C during sampling, which are needed for stressors where a ceiling or peak OEL exists, for dangerous exposures to permanent gas-type contaminants, and for immediately dangerous to life or health (IDLH) conditions. Selective and accurate real-time detection instruments are not available for all air contaminants, but exposure magnitude information may be provided. The large amounts of data from continuous monitoring and the ability to correlate exposure maxima to specific tasks are also important. An exposure assessment role exists for selective and nonselective monitors, and in some cases, similar accuracy and precision are provided compared to laboratory analyses. Continuous monitoring may be of value when the alternative is the collection of a few C TWA data points. Digitized personal monitor data can support the automation of some exposure control decisions or allow such decisions to be made by people in near real-time. The emerging Internet of Things (IoT) offers opportunities to integrate digital exposure data into decision-making to increase both efficiency and safety. The perceived and real uncertainty associated with real-time exposure assessments may be lessened with work to rule out the presence of know interferents and confirm the presence of target analytes.

Modeling the environmental, health, and safety aspects of xylene isomer emission from storage tanks in petrochemical industries, Iran.

The release of xylene isomers from storage tanks poses a significant threat to petrochemical industries, and their safe transportation and storage is a widely researched topic. This paper focused on modeling the environmental, health, and safety effects of P-xylene and O-xylene leakage from storage tanks via Areal Locations of Hazardous Atmospheres (ALOHA) and Wireless Information System for Emergency Responders (WISER). The meteorological data of the area, characteristics of the tanks, and the roughness of the land surrounding the tanks were used to run the ALOHA model. The dispersion distances of P-xylene and O-xylene toxic and flammable vapor clouds were estimated according to the Immediately Dangerous to Life or Health (IDLH) and lower explosive limit (LEL) criteria. Also, the levels of thermal radiation due to the burning of P-xylene and O-xylene were estimated. The results showed that in the cold seasons, the IDLH was a maximum distance of 62m and 45m for P-xylene and O-xylene, respectively. The LEL criteria were 10% with a magnitude of 1100ppm for a maximum distance of 54m and 35m for P-xylene and O-xylene, respectively. The maximum distance of 20m for O-xylene based on the results of the LEL criteria of 60% (6600ppm) was attained in the warm seasons. They are potentially lethal within 60s at 21m (10.0kW/m2) when burned. The WISER software predicted the protective distance for xylene isomers to be about 300m. The results show that creating a protective zone around the P-xylene and O-xylene tanks with a radius of 54m is necessary to reduce hazards.

Low Cost Wearable Multi-Gas Chemical Sensor Badges for First Responders

IntroductionToxic Industrial Chemicals (TICs) are chemical substances which produce toxic effects if encountered in sufficient quantities and/or long durations. TICs are a great concern for the U.S. Department of Homeland Security (DHS) since they would be easier for terrorists to obtain and use than Chemical Warfare Agents (CWAs). Therefore, first responders need a small, rugged, wearable, monitor that alerts them when they are facing TICs, and if so, what is present and at what levels. While there are many commercially available handheld and personal gas monitors for TICs, most are bulky (more than 0.75” in thickness) and expensive ($500 or more). These monitors are primarily used in cities having a population of 100k or more. Hence, there is a need for a low cost (less than $100) wearable multi-gas sensor. Such wearable sensors will also find use in the much bigger application of industrial worker safety monitoring.To address this need TDA Research (TDA) has developed a simple, low cost wearable smart chemical sensor badge that has high sensitivity and selectivity to multiple TICs at trace (low parts per million) concentrations and triggers distinct alarms at permissible exposure limit (PEL), and Immediately Dangerous to Life or Health (IDLH) concentrations. Our wearable smart sensor badge uses a Lab-on-a-chip, is smaller than 2” x 2” x 0.75”, and can detect multiple TICs ( 4 to 6) of interest, and has a low rate of false alarms so that easy and widespread deployment can be achieved.TDA's sensorWe have demonstrated the operation of the sensor in a fully integrated prototype to detect four to six TICs among the H2S, NH3, PH3, HCN, Cl2, and NO2 at ppm levels and produce an electrical signal that can be used to identify and quantify them. We then obtained performance data that included results for these TICs both separately and together and in the presence of interferents, such as diesel and bleach. The sensor response was correlated and corrected based on ambient temperature, relative humidity levels and the air flow rate through the sensor. This low cost sensor is built using commercial-off-the-shelf (COTS) components along with TDA proprietary media and detection/quantification algorithms to detect and quantify TICs, eliminating false positives and false negatives. The sensors also have the ability to generate multiple alarms (audible, visual, and vibrate) at high (IDLH) and low (PEL) concentrations for four or more of the TICs in a small wearable form factor. TDA’s sensor has the unique ability to distinguish between different volatile organic compounds (VOCs) and oxidizes (Cl2, NO2 and even ozone). The attached figure is a photo of the TDA sensor. The results from the TDA sensor development and their performance under different threats at different humidity and temperature levels will be presented at the meeting. Figure 1

Development of BINOL-Si complexes with large stokes shifts and their application as chemodosimeters for nerve agent

Three fluorescent BINOL-Si complexes (FS1, FS2 and FS3) were rationally designed and synthesized to detect diethyl chlorophosphate (DCP), a mimic of lethal nerve agents. These three fluorescent probes showed green, yellow and orange fluorescence, respectively. Moreover, the series of fluorescent probes has the characteristics of fast response time (≤ 4 s), low detection limit (0.0097 μmol/L), high sensitivity and naked eye detection. More important, a fiber optic sensor capable of detecting DCP vapor in real time was also prepared for the first time, the lowest detection limits (down to 4.4 ppb) were all lower than that of the IDLH (immediately dangerous to life or health) concentration of Sarin (7.0 ppb).

Effect of substrate temperature on physicochemical and gas sensing properties of sprayed orthorhombic V2O5 thin films

The chemical spray (CSP) deposition method has been used to deposit orthorhombic V2O5 thin films onto glass substrate at different substrate temperatures. Raman spectra indicate that films are in orthorhombic V2O5 phase. The FE-SEM micrographs show the formation of nanorods-like morphology. The EDAX study shows that the films are in sub-stoichiometric proportion of V2O5. The presence of V5+ oxidation state of vanadium in V2O5 film is confirmed using XPS study. Selectivity study shows that V2O5 film is a highly promising candidate for selective detection of NO2 gas at moderate working temperature of 200 °C. For V2O5 film deposited at 400 °C, the 20.3% NO2 response for 100 ppm concentration is obtained with response and recovery times of 17 s and 185 s, respectively. The lower NO2 gas detection limit is found to be 20 ppm which is equal to immediately dangerous to life or health (IDLH) value. Finally, role of oxygen ion vacancies in NO2 gas sensing mechanism based on formation of reduced V2O5-X species is discussed.

Simulation of Hydrogen Sulfide Emission from Deep-Pit Manure Storage During Agitation

Abstract. Human and animal exposure to hydrogen sulfide (H2S) in animal barns has long been a serious issue due to the acute and chronic toxicity of H2S. The H2S concentration in the room air of deep-pit swine barns is usually within hundreds of parts per billion by volume; however, it can sharply increase to hundreds and even thousands of parts per million (ppm) during manure agitation and pump-out. To explore the sudden release and concentration distribution of H2S, this study collected and analyzed samples from varying depths of a normal non-foaming barn and a foaming barn and then mathematically simulated the H2S concentrations and emissions in the pit headspace and room air for both barns during pit agitation. Simulations were conducted for six ventilation scenarios, or six different combinations of pit fan and wall fan ventilation rates. The simulation results suggested that pit ventilation was more effective than wall ventilation in decreasing H2S concentration in room air where pigs may be housed during agitation. A minimal pit ventilation rate of 40 cfm per pig was necessary to lower the peak concentration in room air to less than the permissible exposure limit of 20 ppm. The simulation results also indicated that gas bubble release during agitation accounted for the main part (81%) of H2S emission in the foaming barn, and expedited molecular diffusion contributed the main part (70.2%) of H2S emission in the non-foaming barn. The disturbed air-manure interface during agitation induced a pH decrease and therefore increased the apparent overall mass transfer coefficient of H2S, resulting in a substantially increased mass transfer rate and concentration. The immediately dangerous to life or health (IDLH) concentration of 100 ppm may be reached during pit agitation if pit fan ventilation is not fully provided, and the duration of the exceedance could be more than 30 min. The results provide empirical data for future simulation of spatial and temporal H2S distribution and are beneficial for developing methods to control H2S below hazardous levels so that the health and safety of workers can be better secured. Keywords: Agricultural safety, Deep-pit storage, Hydrogen sulfide concentration, Sulfide distribution, Swine manure.

Palladium (Pd) sensitized molybdenum trioxide (MoO3) nanobelts for nitrogen dioxide (NO2) gas detection

The MoO3 nanobelts have been grown onto the glass substrates using chemical spray pyrolysis (CSP) deposition technique at optimized substrate temperature of 400°C. XRD study shows that the film is polycrystalline in nature and possesses an orthorhombic crystal structure. The FE-SEM micrographs show the formation of nanobelts-like morphology of MoO3. The presence of Pd and its oxidation states in Pd-sensitized MoO3 film is confirmed using EDAX and XPS study, respectively. The percentage gas response is defined as |Rg-Ra|Ra×100% where, Ra and Rg are the film resistances in presence of air and analyte gas, respectively. Before Pd sensitization, MoO3 nanobelts show NO2 gas response of 68% for 100ppm concentration at operating temperature of 200°C with response and recovery times of 15s and 150s, respectively. Selectivity coefficient study shows that the Pd-sensitized MoO3 nanobelts are more sensitive and selective towards NO2 gas among various gases such as NH3, H2S, CO, CO2 and SO2. The Pd-sensitized MoO3 nanobelts shows the enhanced response of 95.3% towards 100ppm NO2 gas concentration with response and recovery times of 74s and 297s, respectively. The lower detection limit is found to be 5ppm which is four times less than immediately dangerous to life or health (IDLH) value of 20ppm. Finally, the proposed NO2 gas sensing mechanism based on chemisorption model is discussed.

Locating Firefighters in Immediately Dangerous to Life or Health Environments

Locating injured firefighters is critical in immediately dangerous to life or health (IDLH) environments where they can be overcome by smoke, or exposed to other environmental stressors. Auditory and visual communication technologies such as Personal Alert Safety System (PASS) devices and radio communications are often used to locate firefighters entering IDLH environments. However, the reliability of these communication methods can be detrimental in pinpointing the location of an injured firefighter due to unconsciousness, disorientation, or unfamiliarity with the layout of the building. The purpose of this study was to identify the effects of visibility conditions, rescuer familiarity with the search area, and search and rescue method on the time needed to locate victims in an IDLH environment. Results of the study indicated that time needed to locate victims could be significantly reduced when using a radio frequency identification (RFID) based real time locating method compared to a traditional grid search rescue method.

Orthorhombic MoO3 nanobelts based NO2 gas sensor

Molybdenum trioxide (MoO3) nanobelts have been deposited onto the glass substrates using chemical spray pyrolysis (CSP) deposition method. The XRD patterns reveal that films are polycrystalline having an orthorhombic crystal structure. Raman spectra confirm that the films are orthorhombic in phase. The XPS study shows the presence of two well resolved spectral lines of Mo-3d core levels appearing at the binding energy values of 232.82eV and 235.95eV corresponding to Mo-3d5/2 and Mo-3d3/2, respectively. These binding energy values are assigned to Mo6+ oxidation state of fully oxidized MoO3. The FE-SEM micrographs show the formation of nanobelts-like morphology. The AFM micrographs reveal that the RMS surface roughness increases from 16.5nm to 17.5nm with increase in film thickness from 470nm to 612nm and then decreases to 16nm for 633nm film thickness. The band gap energy is found to be decreased from 3.40eV to 3.38eV. To understand the electronic transport phenomenon in MoO3 thin films, dielectric properties are studied. For 612nm film thickness, the highest NO2 gas response of 68% is obtained at an operating temperature of 200°C for 100ppm concentration with response and recovery times of 15s and 150s, respectively. The lower detection limit is found to be 10ppm which is half of the immediately dangerous to life or health (IDLH) value of 20ppm. Finally, NO2 gas sensing mechanism in an orthorhombic MoO3 crystal structure is discussed in detail.

Toxic Gas Emissions from Damaged Lithium Ion Batteries—Analysis and Safety Enhancement Solution

Lithium ion batteries play an increasing role in everyday life, giving power to handheld devices or being used in stationary storage solutions. Especially for medium or large scale solutions, the latter application confines a huge amount of energy within a small volume; however, increasing the hazard potential far above the common level. Furthermore, as the safety hazards of lithium ion cells have been known for years, impressively shown by several burning cars or laptops, the need for a further enhancement of the safety of these systems is rising. This manuscript presents measurements of the gas emission from lithium ion batteries in case of a malfunction for different scenarios, showing a large variety of species with mostly toxic to highly toxic properties. The measurements were carried out using a combination of gas chromatography-mass spectrometry (GC-MS), quadrupole mass spectrometry (QMS), photoacoustic spectroscopy, and chemical analysis. It is shown that the inflammation of a cell can be overcome, also preventing a cascading effect to neighboring cells, but giving rise to worse toxic gas emission. Furthermore, a filtration concept is presented that decreases the concentration of the emitted components significantly and promises filtration below immediately dangerous to life or health (IDLH) equivalent levels.

Exposure Assessment for Carbon Dioxide Gas: Full Shift Average and Short-Term Measurement Approaches

Carbon dioxide (CO2) makes up a relatively small percentage of atmospheric gases, yet when used or produced in large quantities as a gas, a liquid, or a solid (dry ice), substantial airborne exposures may occur. Exposure to elevated CO2 concentrations may elicit toxicity, even with oxygen concentrations that are not considered dangerous per se. Full-shift sampling approaches to measure 8-hr time weighted average (TWA) CO2 exposures are used in many facilities where CO2 gas may be present. The need to assess rapidly fluctuating CO2 levels that may approach immediately dangerous to life or health (IDLH) conditions should also be a concern, and several methods for doing so using fast responding measurement tools are discussed in this paper. Colorimetric detector tubes, a non-dispersive infrared (NDIR) detector, and a portable Fourier transform infrared (FTIR) spectroscopy instrument were evaluated in a laboratory environment using a flow-through standard generation system and were found to provide suitable accuracy and precision for assessing rapid fluctuations in CO2 concentration, with a possible effect related to humidity noted only for the detector tubes. These tools were used in the field to select locations and times for grab sampling and personal full-shift sampling, which provided laboratory analysis data to confirm IDLH conditions and 8-hr TWA exposure information. Fluctuating CO2 exposures are exemplified through field work results from several workplaces. In a brewery, brief CO2 exposures above the IDLH value occurred when large volumes of CO2-containing liquid were released for disposal, but 8-hr TWA exposures were not found to exceed the permissible level. In a frozen food production facility nearly constant exposure to CO2 concentrations above the permissible 8-hr TWA value were seen, as well as brief exposures above the IDLH concentration which were associated with specific tasks where liquid CO2 was used. In a poultry processing facility the use of dry ice to quickly freeze product produced a nearly constant CO2 concentration that caused exposures to approach the permissible 8-hr TWA exposure value.

A novel electronic nose based on porous In2O3 microtubes sensor array for the discrimination of VOCs

We have innovatively developed an electronic nose consisting of only one type of semiconductor metal oxide (SMO) material. The representative SMO material, porous In2O3 microtubes in this work, offered great surface area and large gas penetration channels. By using a solvent casting process, different amounts of porous In2O3 microtubes were coated on Al2O3 substrate, forming a resistometric SMO sensor array-based electronic nose. Each sensing unit in the electronic nose exhibited independent response toward ethanol. We have successfully applied this electronic nose to distinguish four alcohols at the same concentrations (100ppm), and also utilized the electronic nose for the discrimination of 14 volatile organic compounds (VOCs). Clear differentiation among all the 14 VOCs both at their immediately dangerous to life or health (IDLH) and the permissible exposure limit (PEL) concentrations has been achieved with no errors or misclassifications. We expect that this method will expand the application of SMO sensor array-based electronic nose which has been largely limited by the selection of commercially available SMOs and dopants.

Risk Analysis of Environmental Pollution by Secondary Hydrogen Chloride from Leakage of Phosphorus Trichloride

This study aims to analyse the influence of the pollution of hydrogen chloride which is the side effect of the leakage accident of a 50m3 phosphorus trichloride tank. When the leakage source intensity is 1.06kg/s with the leakage time of 30 minutes, and the distance is about 2700m away from the highest allowable concentration (0.05mg/m3) in air of residential areas, which goes beyond about the distance of 700m over the "Comprehensive emission standard of air pollutants" (GB16297-1996) table 2 (100mg/m3, new sources of pollution emission limits), however, the mean value of hydrogen chloride concentration beyond 400m is less than the that of IDLH (immediately dangerous to life or health concentration), and no half lethal concentration (LC50) appears. The scope and extent of pollution can be significantly reduced by timely using fire water to eliminate smoke to change hydrogen chloride into hydrochloric acid fog and make them drop in a lower position.

Colorimetric sensor arrays: Interplay of geometry, substrate and immobilization

This study addresses the interplay of geometry, substrate, and dye immobilization method on colorimetric sensor array performance. Arrays of cross-responsive dyes were exposed to either ammonia or sulfur dioxide gas at their permissible exposure levels (PEL) or their immediately dangerous to life or health (IDLH) concentrations and their colorimetric responses analyzed. Two-dimensional and linear arrays in flow cells were compared for flow path uniformity. Substrate effects were explored using arrays of 36 dyes immobilized in organically modified silica sol–gel (ormosil) formulations printed on six common substrates in three classes: impermeable (glass slides and polyethylene terephthalate), cellulose based (printer paper and chromatography paper with silica gel), and porous polymer membranes (polypropylene and polyvinylidene difluoride). The effect of immobilization of dyes in an ormosil versus in a plasticizer (i.e., a viscous semi-liquid) was also compared. The linear geometry showed a more homogeneous flow path than obtained with the two-dimensional array, which contributes to higher overall response, faster response, and better reproducibility. Arrays printed on impermeable substrates showed long response times attributed to slow diffusion of the analyte through the spot, and those printed on cellulose based substrates showed high noise caused by macroscale surface texturing. Arrays printed on porous polymer substrates showed the best spot quality and reproducibility, fastest response, and lowest noise. Finally, plasticizer and ormosils proved to be comparable immobilization matrices for colorants, and the preferred choice depends on the combination of dye, immobilization method, and substrate.

A societal risk study for transportation of class-3 hazmats – A case of Indian state highways

United Nations Class-3 hazardous materials (hazmats) are basically liquid products and transported in road tankers under ambient temperature and atmospheric pressure. They are mostly flammables and some of them are toxic (e.g. benzene) as well. The spillages due to collision related incidents involving the road tankers, carrying such hazmats through highways, pose not only flammability hazards due to pool fire, flash fire and vapor cloud explosion (VCE), but create substantial toxic hazards also. The paper presents the risk-based study of route evaluation of two state highways and one urban city road in western India on account of transportation of class-3 hazmats, namely benzene, toluene, p-xylene, methanol, cyclohexane and acetone. A comparative evaluation of study routes was undertaken based on their societal risks presented in terms of F–N curves and assessed against HSE, UK as well as VROM, The Netherlands risk acceptance criteria. Societal risks contribution of cyclohexane to the overall flammability risk mainly VCE is found to be the highest followed by acetone and benzene compared to other study hazmats. This is due to highly explosive nature of cyclohexane resulting into vapor cloud explosion. While acetone and methanol pool fires are likely to cause larger area of damage compared to others, benzene supersedes others as far as toxicity risk is concerned and larger evacuation area is encountered, as it poses greater Immediately Dangerous to Life or Health (IDLH) distance than others. Besides, study of initial isolation distance following an accident in case of benzene tanker found that benzene spillage requires larger initial isolation distance than others and so are the day and night protective action zone distances.

Consequence Evaluation of Toxic Chemical Releases by ALOHA

Abstract Incidence of chemical leakage presents a severe threat to the safety of residents in close proximity, air quality and occupational safety. And as such, the prevention and simulation of chemical leakage has become one of the most important topics in the fields of environmental protection and process safety. In this study, the areal location of hazardous atmospheres (ALOHA) models have been chosen to simulate the release of liquid and gaseous toxic substances of three unnamed plants at a chemical complex. The simulation involves the release of chlorine, epichlorohydrin, and phosgene (these three toxic substances have been chosen for their significantly larger quantities and higher threat to safety) in their storage tanks to analyze the results from the scenario for further analyses and comparisons. The results are then presented in accordance to the emergency response planning guidelines (ERPG) and corresponding immediately dangerous to life or health (IDLH) values. We discovered the spread affection scope of plant C had the higher leaking of phosgene, the next was the plant A for leaking of chlorine, and the final was the plant B for leaking of epichlorohydrin. The results were then used in the deductions of relevant analyses of consequences and risk assessments, which would be made available to the sector in the hopes of minimizing the potential impact from such incidents in the future.