Chemical Safety Concerns of Sulfur Mustard Analog, 2-Chloroethyl Ethyl Sulfide, in Laboratory Study

: Sulfur mustard (SM), a classic chemical weapon in the vesicant category, can induce severe damage, for which the therapy is still limited even today. Laboratory work is essential in unveiling toxicological effects and developing medical countermeasures. Sulfur mustard analog 2-chloroethyl ethyl sulfide (CEES), is employed in the lab for less toxicity. However, due to its similar characteristics to SM (being oily, hydrophobic, and volatile), the manipulation of CEES still needs special attention to avoid personnel injury and laboratory pollution. Here, to clear the chemical safety concerns in the laboratory study of CEES, the working procedure and experimental data are summarized, which might help educate new researchers to be skilled and professional.

Automated Sample Preparation and Data Collection Workflow for High-Throughput In Vitro Metabolomics

Regulatory bodies have started to recognise the value of in vitro screening and metabolomics as two types of new approach methodologies (NAMs) for chemical risk assessments, yet few high-throughput in vitro toxicometabolomics studies have been reported. A significant challenge is to implement automated sample preparation of the low biomass samples typically used for in vitro screening. Building on previous work, we have developed, characterised and demonstrated an automated sample preparation and analysis workflow for in vitro metabolomics of HepaRG cells in 96-well microplates using a Biomek i7 Hybrid Workstation (Beckman Coulter) and Orbitrap Elite (Thermo Scientific) high-resolution nanoelectrospray direct infusion mass spectrometry (nESI-DIMS), across polar metabolites and lipids. The experimental conditions evaluated included the day of metabolite extraction, order of extraction of samples in 96-well microplates, position of the 96-well microplate on the instrument’s deck and well location within a microplate. By using the median relative standard deviation (mRSD (%)) of spectral features, we have demonstrated good repeatability of the workflow (final mRSD < 30%) with a low percentage of features outside the threshold applied for statistical analysis. To improve the quality of the automated workflow further, small method modifications were made and then applied to a large cohort study (4860 sample infusions across three nESI-DIMS assays), which confirmed very high repeatability of the whole workflow from cell culturing to metabolite measurements, whilst providing a significant improvement in sample throughput. It is envisioned that the automated in vitro metabolomics workflow will help to advance the application of metabolomics (as a part of NAMs) in chemical safety, primarily as an approach for high throughput screening and prioritisation.

Joint Labor and Environmental Networks’ Chemical Disaster Prevention Recommendations to the U.S. Chemical Safety and Hazard Investigation Board

More than 180 preventable incidents at hazardous chemicals facilities occur each year, resulting in deaths, injuries, evacuations, shelter in place orders, environmental contamination, and facility shutdowns with permanent job loss. As of June 17, 2021, the Chemical Safety Board (CSB) had nineteen open site investigations of incidents that in total killed thirty-two people, injured at least eighty-seven people, led to thousands of residents sheltering in place or evacuating, and resulted in many millions of dollars in property damage. This document outlines twenty-one practical and measurable actions that the CSB can take to rebuild its investigative and recommendations capacity; set clear priorities for agency action; reform its governance policies; and increase public transparency and engagement. The proposed actions address incident investigations, safety studies, safety recommendations, agency governance, and public transparency and engagement.

Integrating in vitro metabolomics with a 96-well high-throughput screening platform

Introduction High-throughput screening (HTS) is emerging as an approach to support decision-making in chemical safety assessments. In parallel, in vitro metabolomics is a promising approach that can help accelerate the transition from animal models to high-throughput cell-based models in toxicity testing. Objective In this study we establish and evaluate a high-throughput metabolomics workflow that is compatible with a 96-well HTS platform employing 50,000 hepatocytes of HepaRG per well. Methods Low biomass cell samples were extracted for metabolomics analyses using a newly established semi-automated protocol, and the intracellular metabolites were analysed using a high-resolution spectral-stitching nanoelectrospray direct infusion mass spectrometry (nESI-DIMS) method that was modified for low sample biomass. Results The method was assessed with respect to sensitivity and repeatability of the entire workflow from cell culturing and sampling to measurement of the metabolic phenotype, demonstrating sufficient sensitivity (> 3000 features in hepatocyte extracts) and intra- and inter-plate repeatability for polar nESI-DIMS assays (median relative standard deviation < 30%). The assays were employed for a proof-of-principle toxicological study with a model toxicant, cadmium chloride, revealing changes in the metabolome across five sampling times in the 48-h exposure period. To allow the option for lipidomics analyses, the solvent system was extended by establishing separate extraction methods for polar metabolites and lipids. Conclusions Experimental, analytical and informatics workflows reported here met pre-defined criteria in terms of sensitivity, repeatability and ability to detect metabolome changes induced by a toxicant and are ready for application in metabolomics-driven toxicity testing to complement HTS assays.