Inhalation Exposure Research Articles

Alterations in the expression of genes involved in the mitochondrial apoptotic pathway upon exposure to lead oxide nanoparticles

Introduction. Lead production technologies pollute the air with aerosol nanoparticles, including those of lead oxide (PbO NPs). Lead can cause oxidative stress that leads to cell death. Experimental studies of effects of PbO NPs at the gene transcription level will expand our knowledge of the mechanisms of PbO NP toxicity and improve assessment of health risks for the population exposed to them. The purpose was to study the expression of genes involved in antioxidant protection and apoptosis following subchronic inhalation exposure of lead nanoparticles to rats. Materials and methods. Female albino rats were exposed to PbO NPs in an inhalation chamber at a concentration of 1.55 ± 0.06 mg/m3, 4 hours a day, 5 days a week for 1 month; the control group breathed clean air in a similar chamber. After exposure cessation, RNA was isolated from fragments of the olfactory bulb, cerebellum, lung, and liver. Expression of the P53, BAX, BCL-2, GSTM1, GSTP1, and SOD2 genes was determined by quantitative real-time PCR. The data was analyzed using the Mann-Whitney test. Results. In the olfactory bulb, BCL-2 gene expression was significantly lower, while that of P53 was higher in the exposed rodents compared to the controls. In the cerebellum of the exposed animals, BAX and P53 genes expression was statistically higher and lower than in the control group, respectively. BCL-2 gene expression in the liver was significantly lower in the exposed group. Limitations. The experiment involved only female rats, so it does not take into account sex differences and considers only gene expression, neglecting post-translational mechanisms and protein expression. Conclusion. Inhalation exposure to PbO NPs at the concentration of 1.55 ± 0.06 mg/m3 causes changes in the expression of genes associated with mitochondrial apoptosis in the brain and liver, but not in the lungs of laboratory rats.

Stereoselective In Vitro Metabolism, Hepatotoxicity, and Cytotoxic Effects of Four Enantiomers of the Fungicide Propiconazole.

Propiconazole (PRO) is a chiral triazole fungicide that has been widely used for several years. However, its metabolic characteristics and hepatotoxicity in the chiral level environment remain unclear. In this study, the stereoselective behavior of PRO was investigated by using liver microsome incubation, cell viability assay, inhalation exposure, and molecular docking. Our results demonstrated that the isomers trans (-)-2R,4R-PRO and cis (+)-2R,4S-PRO exhibited slower metabolic rates in rat liver microsomes. The cytochrome P450 family 1 subfamily A polypeptide 2 enzyme was found to play a key role in the metabolism of PRO, contributing to its stereoselective behavior. Histopathological and cell viability results showed that exposure to rac-PRO could induce severe hepatotoxicity in mice. This effect might be related to the accumulation of cis (+)-2R,4S-PRO in the liver, which has a slow metabolism and is highly toxic. Our findings indicate that avoiding the application of cis (+)-2R,4S-PRO in agriculture can significantly reduce adverse effects on nontarget organisms.

Evaluation of some physicochemical parameters and health risks associated with potentially toxic elements (PTEs) in agricultural soils from the southwest region of Ethiopia

In this study, soil samples collected from Burusa and Bure agricultural sectors were analyzed for their physicochemical parameters and potentially toxic elements (Fe, Mn, Zn, Cu, Co, B, Se, Ni, Cr, Pb, Cd, As, and Hg). Physicochemical parameters were analyzed according to AOAC methods. For quantification of PTEs, the soil samples were digested by using aquaregia (HCl: HNO3; 3:1) and 5 mL of H2O2 (30%) at a digestion temperature of 250°C for 3 hours prior to ICP-OES analysis. The percent recoveries (%R) and relative standard deviation (%RSD) of this method ranged from 83 to 106% and 0.39 to 9.2%, respectively. The LODs and LOQ values were in the range of 4.3 × 10-4-5.3 × 10-2 mg/L and 1.4 × 10-3-1.76 × 10-1 mg/L, respectively. The analyzed mean values of physicochemical parameter including pH, temperature, electrical conductivity, moisture, organic matter and nitrogen content were found in the range of 4.85-6.47, 20.5-21.4°C, 101.6-230.7 µS/cm, 8.67-20.7%, 0.677-1.81% and 5.81-6.85%, respectively. The average amount of potentially toxic elements found in the soil samples were ranged as 57073-81279, 1185-3255, 41.0-72.2, 12.6-29.2, 18.8-50.8, 25.0-40.5, 42.2-60.8, 13.6-34.5, 41.9- 67.2, 25.0-59.4, 9.92-13.3, 0.933-1.12 and 4.97-8.63 in mg/kg for Fe, Mn, Zn, Cu, Co, B, Se, Ni, Cr, Pb, Cd, As and Hg, respectively. The highest concentrations of among the entire PTEs were recorded for Fe, followed by Mn, in the analyzed soil samples. All the studied elements are below the FAO/WHO permissible limit except Fe, Se, Cd, and Hg for all analyzed soil samples and Mn for the Bure soil sample. The target hazard quotient (THQ) and hazard index (HI) values are <1, suggesting an insignificant non-carcinogenic risk of the heavy metals to the adults via ingestion, inhalation, and dermal contact exposure of agricultural soils. Likewise, the individual element incremental lifetime cancer risk (ILCR) occurrence for all studied soil samples is below 1 × 10-4. The total ILCR of potentially toxic heavy metals (Ni, Cr, Pb, Cd and As) resulting from ingestion, inhalation, and dermal contact exposure of agricultural soil by an adult population indicate a slightly higher potential cancer risk (> 1 × 10-4) for soil samples obtained from Bure S1, Bure S2, and Bure S3. Therefore, continuous monitoring of these harmful elements should be made by agricultural sectors and responsible government regulatory authorities are crucial to prevent PTEs related to agricultural soils in Ethiopia.

Completely defined cell culture medium for advanced alveolar models

Abstract In vitro alveolar models are an important tool study respiratory physiology, investigate lung diseases, develop and test new therapies, and simulate inhalation exposure to environmental pollutants or therapeutic agents. A defined cell culture medium is essential for maintaining consistent and reliable in vitro models. In this study a defined cell culture medium for advanced alveolar models based on epithelial A549 cell line and endothelial EaHy926 cell line is developed. Cellular survival was proven by quantification of LDH release. It was shown that co-culture of the cells enhances cellular survival compared to the endothelial monoculture. The formation of a homogeneous monolayer on laminin coated membranes was confirmed by actin staining. Further, the expression of cell type specific proteins (endothelial: CD31, VE-cadherin; epithelial: ZO1 and E-cadherin) was shown. Overall, we demonstrated a completely defined cell culture medium that can be used for the setup of an advanced in vitro alveolar model for biomedical application like drug development or breath gas analysis.

Inhalation exposure to dihydroxyacetone promotes lung injury and pulmonary fibrosis in A/J mice

Inhalation exposure to dihydroxyacetone promotes lung injury and pulmonary fibrosis in A/J mice

Development of plutonium fuel facility decommissioning technology to accelerate glovebox dismantling and reduce air-fed suits based operations

The Plutonium Fuel Fabrication Facility is currently in the decommissioning phase, with glovebox dismantling operations ongoing since 2010. During conventional glovebox dismantling operations, the glovebox to be dismantled is enclosed within plastic tents to contain contamination. The glovebox is then dismantled by workers wearing air-fed suits with thermal or mechanical cutting tools, which typically generate dross or sparks in the form of radioactive aerosols during cutting. Despite the longevity and meticulous organization of this manual method, the workload remains considerable, while the allowable working time is limited. In addition, the potential for inhalation exposure to plutonium is elevated in the event of an accident given the contamination of the work area. To overcome disadvantages associated with conventional glovebox dismantling methods, new methods are currently being developed. The primary objective is to reduce the reliance on operation based on air-fed suits and enhance worker safety by introducing remote equipment and a new floor-reinforcing panel. Another objective is to suppress waste generation by reusing all equipment on multiple occasions which is achieved by developing a containment system that have a large open port with a pallet for the storage and reuse of equipment for successive operations. Furthermore, a glove operation compartment is designed and tested for the manual handling of dismantled materials as an additional strategy to reduce work based on air-fed suits and mitigate secondary waste generation.

Acute and Chronic Health Risk Assessment for Automobile Users Due to Inhalation Exposure to Volatile Organic Compounds and Carbonyl Compounds

Since automobiles are the primary means of transportation in modern society, the assessment of health effects from acute and chronic exposure to pollutants in automobiles is crucial. In this study, the concentration of volatile organic compounds (VOCs), carbonyl compounds, and odor-including substances in newly manufactured automobiles were analyzed, and exposure factors reflecting automobile user characteristics were selected for health risk assessment. Toluene exhibited the highest concentration (203.5 ± 379.3 μg/m3) among all measured pollutants. The acute and chronic non-carcinogenic health risk assessments indicated that the pollutants did not exceed their standards in any of the automobiles, suggesting no immediate health risks. However, in the chronic carcinogenic health risk assessment, acrylonitrile exceeded its standard value in all automobiles, indicating potential carcinogenic effects from long-term exposure. The findings suggest that careful estimation of lifetime exposure effects to pollutants inside new automobiles is required. Future studies should investigate specific pollutants generated by automotive materials and manufacturing processes to identify pollutant sources and reduce health risks to automobile users.

Exploration of the transfluthrin effects on fertility and pregnancy outcomes: An in-vivo study in rat

Transfluthrin (TFL) is a rapid-acting pyrethroid insecticide, commonly used worldwide, however its overuse and or misuse has been associated with adverse effects on human health. This study was designed to investigate the impact of TFL on fertility and pregnancy in Sprague–Dawley rats exposed orally and by inhalation. In this study, 48 adult Sprague–Dawley rats of 6–8 months age group were randomly selected with equal numbers of males and females. Each group was housed separately in a standard laboratory condition and their daily consumption of food and water, along with weight of each group were monitored. The blood was collected from each rat on 0 (zero) and 85th day of oral and inhalation exposure to TFL to determine the hormone levels by ELISA. The findings revealed that TFL exposure through oral and inhalation route reduced hormones level in serum such as testosterone, follicle-stimulating hormone, luteinizing hormone, progesterone, estrogen, and prolactin in both male and female rats. In conclusion, current research suggest the negative effects of TFL exposure on fertility, adversely affecting pregnancy outcomes, reducing the mating rate, and lowering the number of pups. It also stresses the significance of controlling its use to prevent any negative consequences.

Applicability of monitoring data of Hg soil-atmosphere transport in an old mining area for exposure risk assessment

Mercury (Hg) is a widespread pollutant that poses significant risks to both ecosystems and human health. While previous studies have evaluated Hg concentrations in soils, few have measured Hg emissions in areas with high Hg concentrations or related these measurements to estimates of exposure via air inhalation based on Hg flux values. This study addresses this gap by proposing the use of gaseous elemental Hg (GEM) flux measurements for exposure risk assessments, with a particular focus on the importance of inhalation exposure, which has implications for future risk management strategies. Sensitivity analysis of the site-specific exposure and risk estimation model revealed that the fraction of land area in surface water significantly impacted the estimated exposure through air inhalation. Additionally, the analysis showed that the GEM flux measured in situ in a high-Hg concentration area of Itomuka was not directly proportional to the Hg concentration, although the risk estimation model treated it as a function of concentration. Furthermore, we found that the flux values are influenced by both the fraction of land area in surface water and Hg concentration, indicating that this new flux-based indicator should be integrated into exposure risk assessments.

Source appointment and health risk assessment for atmospheric carbonyls in hot tropical city, Vietnam.

The aim of this study is to assess the spatiotemporal variation, sources, and health impacts of the carbonyl compounds (carbonyls) in Ho Chi Minh City (HCMC), the third-most populous city in Southeast Asia. Sampling was conducted according to the US.EPA Method TO-11A, from 2012 to 2016 in both the dry and the rainy seasons at twelve sites. The result shows that the carbonyl mixing ratios are high when compared to typical cities. Formaldehyde, acetaldehyde, and acetone are the most abundant carbonyls together accounting for 89% of the measured carbonyls. The carbonyl mixing ratio in rainy (46.0 ± 32.2ppb) is about twofold higher than that in dry (23.7 ± 10.3ppb). An inverse distance weighting method was adopted to map the spatial distribution of carbonyls across the city. The result shows that the carbonyl levels tended to be high in the city center. Three carbonyl sources are resolved by the PCA/APCS method: industrial sources and solvent usage (54%), vehicle exhausts (24%), cooking emissions (11%). Both lifetime cancer risk (LCR) and non-cancer hazard index (HIs) were calculated to estimate the health impacts on the community due to inhalation exposure to current carbonyl levels. The LCR values vary from 5.31 × 10-6 to 5.75 × 10-5 for formaldehyde higher than those of 6.61 × 10-7 to 1.36 × 10-5 for acetaldehyde, which mostly exceeded the US.EPA recommendation for five age groups. The hazard quotient values are 12.0 to 68.4 for acrolein, 0.44 to 2.84 for acetaldehyde, 0.55 to 1.85 for formaldehyde, and 0.13 to 0.89 for propionaldehyde.

Emitted droplets and aerosols and their transmission when drying hands under an air-jet dryer

When drying hands with a high-speed air jet dryer, the jet impingement on hands can quickly atomize the remnant water on the hand skins into droplets and aerosols. Emission of droplets and liquid aerosols, their spatial transport and the possible inhaling exposure to the hand dryer user remain unclear. This investigation measured the jet flows from a downward air jet dryer, by the particle image velocimetry (PIV), the helium bubble trajectory analysis, and an ultrasonic anemometer. Emission of the droplets when turning over the hands, the droplet spatial motion, and their deposition on human body were photographed by a high speed camera. Concentrations of the liquid aerosols were monitored and the total emitted aerosol numbers and size spectrum were analyzed. The possible inhalation exposure to the emitted liquid aerosols was examined. It is found that number of droplets in size of 0.1 to 0.6 mm can deposit on the mouth and nose and the surrounding face. A typical hand drying process may emit approximately 105 liquid aerosols, of which 93 % are in the submicron size. A hand dryer user may inhale thousands of the emitted liquid aerosols if drying hands without wearing face mask.

Operator exposure and cabin protection in plant protection product application

AbstractTightly sealed driver's cabs can effectively protect the user from exposure when applying crop protection products. Therefore, under certain conditions, users in such cabins can avoid wearing personal protective equipment for skin and eyes. The protective effect depends on the technical design and handling of the different cabin types and can be divided into categories with different levels of protection. Since the level of protection of the different types of cabins and the associated possibility of not wearing personal protective equipment has not been sufficiently scientifically verified in the past, the present study was carried out to close this gap. Field and laboratory test methods were developed and used to assess exposure levels. External contamination of the cabin was measured using various dosimeters. Exposure inside the cabins was measured on coveralls and gloves to measure dermal exposure and with aerosol sampling pumps to determine inhalation exposure. Tests were conducted on tractors with different cab categories using an air-assisted orchard sprayer as a worst-case scenario for exposure to spray drift. Additionally, an alternative laboratory test method was developed and conducted to evaluate filter efficiency under controlled conditions and compare it with the field tests. The results showed that exposure inside closed cabins was generally low and was not notably correlated with the cabin category. All types of cabins tested were found to provide significant protection from dermal and inhalation exposure.

Evaluation of Health Risk and Heavy Metal Pollution Caused by Dust Storms in Zabol City.

This study investigated the concentrations and compositions of specific elements in total suspended particulate (TSP) samples and the associated ecological, carcinogenic, and non-carcinogenic risks related to the inhalation, ingestion, and dermal absorption of heavy metals. The study focused on adult and pediatric populations in the highly dust-polluted city of Zabol, Iran, during 2022-2023. The samples were analyzed by using inductively coupled plasma optical emission spectrometry (ICP-OES). The concentration of metals in milligram per kilogram (mg/kg) was as follows: Al (75053) > Ca (8206) > Fe (5439) > Mg (5323) > Zn (15.27) > Pb (3.66) > Cr (3.38) > Cd (0.011); according to the results, the highest amount of metals related to aluminum and calcium in dust particles. The calculated individual indices, including the ecological risk index (ERI), pollution factor (Cfi), and geographic accumulation index (Igeo), indicated that calcium exhibited minimal pollution, while the metal samples (Al, Mg, Fe, Cd, Cr, Pb, and Zn) were categorized as uncontaminated. The results revealed that the ecological risk factor (Er) is below 40, indicating a low level of contamination. Additionally, the pollution level determined by the ecological risk potential (RI) was less than 150, suggesting a low probability of contamination. Ingestion posed the highest average hazard quotient (HQ) values for both children and adults in terms of non-carcinogenic risk assessment, while cutaneous and inhalation exposures showed lower values. Furthermore, the hazard index (HI) for heavy metals remained below the safe threshold of 1. The risk index (RI) values for lead, cadmium, and chromium were all below 1 × 10-6 in both adult and pediatric populations. The United States Environmental Protection Agency (USEPA) guidelines suggest an acceptable level of carcinogenicity for all heavy metals, indicating a potential risk of cancer associated with the presence of these metals in suspended particles in Zabol.

Chronic inhalation exposure to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) alters cardiac collagen in Wistar rats.

2,4-dichlorophenoxyacetic acid (2,4-D) is one of the most used in the world and exposure to herbicides can affect animals and humans, causing toxic effects that include cardiotoxicity. This is the first study to evaluate cardiac remodeling after experimental simulation of environmental exposure by chronic inhalation (6months) to the herbicide 2,4-D. Thirty male Wistar rats were exposed to two different concentrations of the 2,4-D formulation (low - 187.17mg/m3; and high - 467.93mg/m3) and the control group exposed to nebulization of chloride solution 0.9% sodium. Inhalation exposure lasted 6months. Mice hearts were collected for histology. There was a difference between exposure concentrations in relation to the increase in cardiac collagen (P<0.0001). In mice exposed to a low dose of 2,4-D and a decrease in the fractal dimension of cardiac collagen in the high dose of 2, 4-D (P=0.010). This study shows that chronic inhalation exposure to 2,4-D induces cardiotoxicity in rats, characterized by extracellular matrix reorganization and changes in collagen levels, highlighting the impact of the exposure route on cardiac outcomes. There was no difference in relation to anatomical parameters, cardiomyocyte area, collagen types I and III and analysis of arteriole thickness. Chronic exposure at different doses to the 2,4D herbicide had the potential to cause damage to cardiac remodeling by altering cardiac collagen in rats.

Pulmonary Flora-Derived Lipopolysaccharide Mediates Lung-Brain Axis through Activating Microglia Involved in Polystyrene Microplastic-Induced Cognitive Dysfunction.

Microplastics (MPs) have been detected in the atmospheric and the human respiratory system, indicating that the respiratory tract is a significant exposure route for MPs. However, the effect of inhaled MPs on cognitive function has not been adequately studied. Here, a C57BL/6 J mouse model of inhalation exposure to polystyrene MPs (PS-MPs, 5 µm, 60 d) is established by intratracheal instillation. Interestingly, in vivo fluorescence imaging and transmission electron microscopy reveal that PS-MPs do not accumulate in the brain. However, behavioral experiments shows that cognitive function of mice is impaired, accompanied by histopathological damage of lung and brain tissue. Transcriptomic studies in hippocampal and lung tissue have demonstrated key neuroplasticity factors as well as cognitive deficits linked to lung injury, respectively. Mechanistically, the lung-brain axis plays a central role in PS-MPs-induced neurological damage, as demonstrated by pulmonary flora transplantation, lipopolysaccharide (LPS) intervention, and cell co-culture experiments. Together, inhalation of PS-MPs reduces cognitive function by altering the composition of pulmonary flora to produce more LPS and promoting M1 polarization of microglia, which provides new insights into the mechanism of nerve damage caused by inhaled MPs and also sheds new light on the prevention of neurotoxicity of environmental pollutants.

A Neural Circuit For Bergamot Essential Oil-Induced Anxiolytic Effects.

Aromatic essential oils have been shown to relieve anxiety and enhance relaxation, although the neural circuits underlying these effects have remained unknown. Here, it is found that treatment with 1.0% bergamot essential oil (BEO) exerts anxiolytic-like effects through a neural circuit projecting from the anterior olfactory nucleus (AON) to the anterior cingulate cortex (ACC) in acute restraint stress model mice. Collectively, in vivo two-photon calcium imaging, viral tracing, and whole-cell patch clamp recordings show that inhalation exposure to 1.0% BEO can activate glutamatergic projections from the AON to GABAergic neurons in the ACC, which drives inhibition of local glutamatergic neurons (AONGlu→ACCGABA→Glu). Optogenetic or chemogenetic manipulation of this pathway can recapitulate or abolish the BEO-induced anxiolytic-like behavioral effects in mice with ARS. Beyond depicting a previously unrecognized pathway involved in stress response, this study provides a circuit mechanism for the effects of BEO and suggests a potential target for anxiety treatment.

Safety and efficacy of a feed additive consisting of Bacillus subtilisDSM 33862 and Lentilactobacillus buchneriDSM 12856 as a silage additive for all animal species (Lactosan GmbH & Co.KG).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on a formulation of Bacillus subtilis DSM 33862 and Lentilactobacillus buchneri DSM 12856 when used as a technological additive to improve ensiling of fresh plant material. The additive is intended for use with fresh plant material with a dry matter (DM) range of 32%-65% at a proposed minimum concentration of 1 × 108 colony forming units (CFU)/kg fresh plant material to be used for all animal species. The bacterial species B. subtilis and L. buchneri are considered by EFSA to be suitable for the qualified presumption of safety approach to safety assessment. The identity of the strains was established, no acquired antimicrobial resistance genes of concern were detected in any of the two active agents and no evidence of toxigenic potential was found in B. subtilis DSM 33862. Therefore, the FEEDAP Panel concluded that the use of the strains as a silage additive is considered safe for all the animal species, for consumers of products from animals fed with the treated silage and for the environment. Regarding user safety, the additive contains microorganisms and therefore should be considered as a potential skin and respiratory sensitiser. The additive is not irritant to skin or eyes. Inhalation and dermal exposure is considered a risk. These conclusions would apply, in principle, to any preparations containing the active agents. The FEEDAP Panel concluded that the additive containing B. subtilis DSM 33862 and L. buchneri DSM 12856 at a minimum concentration of 1 × 108 CFU/kg fresh material has the potential to extend the aerobic stability of silage prepared from fresh plant materials with a DM range of 32%-65%.

Safety and efficacy of a feed additive consisting of ponceau 4R for its use in baits for freshwater fish (GIFAP).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of ponceau 4R as sensory additives (functional group: (a) colourants: (i) substances that add or restore colour in feedingstuffs). The additive is already authorised for use with cats and dogs and ornamental fish. The additive is intended to be incorporated in freshwater fishing baits up to a maximum of 15 mg/kg in complementary feed in order to colour them. The additive is intended to be incorporated into feed directly in solid form or via an aqueous solution. The additive is not intended for use in aquaculture. The FEEDAP Panel concluded that ponceau 4R is considered safe when used in fish baits for freshwater fish at the maximum proposed dose of 15 mg/kg complementary feed. The use of the feed additive ponceau 4R fish baits for freshwater fish under the conditions of use proposed is of no concern for consumer safety. Ponceau 4R is not skin irritant but should be considered a skin and respiratory sensitiser. Inhalation and dermal exposure are considered a risk. The FEEDAP Panel could not conclude on the eye irritation potential of the additive. In absence of data no conclusion can be reached on the efficacy of ponceau 4R in freshwater fish baits.

Health risks of environmentally persistent free radicals in atmospheric particulate matter during the spring festival travel season in Tainan, Taiwan.

Environmentally persistent free radicals (EPFRs) and polycyclic aromatic hydrocarbons (PAHs) are persistent pollutants in atmospheric particulate matter that are detrimental to human health. This study collected atmospheric particulate matter during and after the spring festival travel season in Tainan, Taiwan, from various locations and analyzed the carbon composition and PAH isomeric ratios to identify the sources. In this study, EPFR concentrations were measured using electron paramagnetic resonance spectroscopy, with the highest concentration found to be 3.04 × 10(12) spins/m3. EPFRs contained predominantly oxygen-centered radicals in PM2.5, which are mainly existed in PM1. The results show that EPFR concentrations on PM, measured per unit volume (spins/m3) or mass (spins/g), were highest during the spring festival travel season. The daily inhalation exposure to the sum of EPFRs and PAHs in PM2.5 was estimated to be equivalent to inhaling 0.11-0.15 cigarette tar EPFRs per day. This report is the first to document EPFRs in environmental atmospheric particulate matters in Taiwan, which has significantly contributed to local air pollution control and reduced exposure risks to public health in Tainan.

Advanced consequence modeling and risk analysis

AbstractWhen performing process hazard analysis (PHA), basic consequence evaluation methods are often sufficient. However, sometimes these approaches lead to overly conservative estimates, and we need to conduct more thorough dispersion modeling to refine the potential impact. This paper will evaluate different methods for determining the consequence severity of a potential release, starting with a basic approach, and ultimately using probit functions. Probit functions are used to predict the lethality of a potential release following acute inhalation exposure from a toxic release. Developing probits to use in modeling can be challenging, for obvious reasons. In the absence of human or animal toxicological data, estimates of “pseudo‐probits” can be used in lieu of values derived from toxicological data. The analysis makes use of the PHAST™ program that uses probits as part of its basic tool set. While probits are not new to the industry, this paper provides a simple method for estimating pseudo‐probits for materials that do not have readily available probit data.