Acute Exposure Guideline Research Articles

Effect of sensing material basicity on excited-state intramolecular proton transfer-based detection of G-series nerve agents

The use of G-series nerve agents represents a significant threat and there is a need for rapid and selective in-field identification. We report that sensing materials composed of ESIPT-based silyl ethers can be used to detect the hydrogen fluoride that is present in phosphonofluoridate agents such as sarin and its simulant di-iso-propyl fluorophosphate (DFP). We find that the ability of the sensing material to detect the hydrogen fluoride in DFP is dependent on the basicity of the nitrogen atom that forms part of the ESIPT moiety upon deprotection. When the pKa of the conjugate acid of the nitrogen atom was lower than that of hydrogen fluoride the ability of the sensing material to detect the acid and hence simulant was curtailed. However, when the pKa of the conjugate acid was 3 or higher, then hydrogen fluoride could be rapidly detected. The best performing sensing material could detect hydrogen fluoride concentrations as low as 3 ppb in DFP of 99 % purity in one minute. Based on sarin having the same purity level, we estimate that it would be detectable at a concentration of ≈40 ppb in one minute, which is lower than the Acute Exposure Guideline 3 (life-threatening effects) of 64 ppb for a 10-min exposure.

Exposure assessment and environmental consequence evaluation of accidental chlorine release in an industrial area

ABSTRACT Simulated accidental releases of chlorine from the premises of a major household products manufacturing company in Nigeria were investigated, with Threat Zones (TZs). The Aerial Location of Hazardous Atmospheres (ALOHA) software was used for the TZ Identification. The Acute Exposure Guidelines (AEGLs) and the Emergency Response Planning Guidelines (ERPGs) were used for TZs determination. All the AEGL values employed in this analysis are for exposure durations of 60 min, which are expected to be sufficient for appropriate mitigating steps to take place during an emergency. Chlorine was not detected in the ambient environment of the factory premises during the study and was thus taken to be within limits. AEGLs TZs following an accidental release of chlorine from 1 cm hole on a chlorine tonner in the factory were 2000 – 2500 m, 966 – 1300 m and 289 – 382 m for AEGL-1, AEGL-2 and AEGL-3, respectively. ERPGs TZs created by the accidental release of chlorine from 1 cm hole on the chlorine tonner stored in the factory were 478 – 630 m, 274 – 362 m and 106 – 139 m for ERPG-1, ERPG-2, and ERPG-3, respectively. Adequate emergency response plan should be put in place to manage accidental chlorine release in the factory

Assessing the application of acute toxic gas standards

Objective: In this paper, we compare acute toxic gas standards developed for occupational, military, and civilian use that predict or establish guidelines for limiting exposure to inhaled toxic gases.Context: Large disparities between guidelines exist for similar exposure scenarios, raising questions about why differences exist, as well as the applicability of each standard. The motivation and rationale behind the development of the standards is explored with emphasis on the experimental data used to set the standards.Methods: The Toxic Gas Assessment Software (TGAS) is used to quantitatively compare current acute exposure standards, such as: Acute Exposure Guidelines (AEGL), Immediate Danger to Life or Health (IDLH), Purser, International Organization for Standardization (ISO 13571), and Federal Aviation Administration (FAA). The TGAS software does this by calculating the body-mass-normalized internal doses of each gas exposure in each standard, which is then plotted on a cumulative distribution function for a normal or susceptible population to visualize the relationship of the standards to each other. To focus the comparison, acute toxic gas standards for five common fire gases, carbon monoxide (CO), hydrogen cyanide (HCN), hydrogen chloride (HCl), nitrogen dioxide (NO2), and acrolein (C3H4O), are explored.Results: It was found that differences between standards can be reconciled when the target population, effect endpoint, and incidence level are taken into account.Conclusion: By analyzing the standards with respect to these factors, we can acquire a better understanding of the applicability of each.