ACS Chemical Health & Safety最新文献

Accurate and precise monitoring of volatile organic compounds (VOCs) and volatile sulfur compounds (VSCs) is critical to protect individuals against occupational and environmental exposure. Whole-air sampling containers are commonly employed in monitoring, such as fused-silica lined (FSL) canisters, polyvinyl fluoride (PVF) bags, and foil-lined bags. However, these containers have not yet been fully validated, and previous recovery studies are weakened by contradictory findings, short study time, no humidified samples, and unfeasibly high concentrations of VOCs and VSCs. This study evaluated FSL canisters, PVF bags, and foil-lined bags for the recovery of VOCs and VSCs over a period of 20 and 14 days, respectively. This recovery evaluation aimed to quantify the recovery over time of 64 VOCs and 14 VSCs at practical concentrations in the previously specified containers. To better represent field samples, sample containers were prepared at a relative humidity (RH) of 40%, with each set prepared at a “high” (20 ppb for VOCs and 500 ppb for VSCs) and “low” concentration (1 ppb for VOCs and 7 ppb for VSCs). Containers were analyzed intermittently throughout the evaluation period, and sample results were modeled using a first-order natural decay model. From the findings, modeling constants were determined by regression, and a majority (70%) of VOC and VSC models were found to be a good fit (R² > 0.8). PVF bags were found to have higher recoveries for many VSCs than foil-lined bags, and were stable for periods similar to or longer than previously believed. FSL canisters showed a full recovery (>90%) for all VOCs and VSCs over the entire length of the evaluation (20 days for VOCs, 14 days for VSCs). Foil-lined bags were found to have lower recoveries for all VSCs compared to PVF bags.

In collaboration with C&EN

This Commentary discusses the most common safety issues observed in a variety of academic and industrial research laboratories over the author’s 45-plus year career. It highlights the issues and provides additional references for further information. The list can serve as a good tool to help laboratories identify potential safety issues in areas commonly overlooked.

Industrial amines are combined with acids in concentrated forms for various applications. Recently, an explosion occurred when a scientist was screening different acids and selected concentrated nitric acid to mix with an aliphatic amine. This Case Study describes the incident and aftermath, the chemistry behind the incident, and a short review of the hazards of mixing oxidizing acids with amines, with a focus on hypergolic fuels. An SOP with recommended reaction setup is described as well as corrective actions that were identified after a safety review.

The intrinsic nature of Research and Development (R&D) activities─the continuous use of new chemicals and development of cutting-edge, sustainable processes at a rapid pace─can increase the potential for Process Safety and Reactive Chemicals accidents. Industrial and academic laboratories have experienced several significant laboratory accidents and near misses. In an effort to decrease laboratory incidents, Dow, with a large global R&D presence, reviewed internal Root Cause Investigations which indicated that improvements were needed in chemical hazard recognition skills, chemical storage and handling, and inventory management. This paper presents a Dow initiative to address and combat such incidents through the charter of a multidisciplinary team composed of Reactive Chemicals, Process Safety, and Environment, Health, & Safety experts along with R&D researchers, who have collaborated to develop and deliver training modules which focus on high-interest safety topics. Module topics were chosen based on recurrence metrics and potential event severity. Modules provide laboratory personnel with basic topic knowledge, specific hazard awareness regarding the topic, and guidance on how to implement appropriate safeguards. The long-term objective is reducing the number and severity of incidents. Over two years, 10 modules have been delivered in various media; at least a quarter of global Dow R&D personnel have independently engaged with this training content, in addition to those directed to it by leaders, peers, safety experts, or training requirements. In addition to the development of enhanced training delivered via multiple platforms, the team has identified and recommended improvements or additions to existing safety management systems designed to identify hazards and control risk.

While preparing 10?600 L of a 25% aqueous solution of sodium chlorite (NaClO₂), the solid salt was spilled and not cleaned up promptly. Combustible materials, including cardboard sheets and polypropylene fabric, became contaminated with solid sodium chlorite. Subsequently, a spark, initiated by inadvertently striking metal drum sealing rings together, ignited the oxidizer-contaminated combustible materials. The fire spread to a polypropylene bag containing 800 kg of sodium chlorite. The contents of the bag detonated causing one fatality, two serious injuries, and extensive property damage. The incident was thoroughly investigated, leading to the conclusion that a series of process safety management failures occurred which created the conditions driving the incident. The investigation is summarized and discussed, with an emphasis on the investigation procedures used to support the root cause analysis and conclusions. Recommendations are provided to help prevent similar incidents.

Material extrusion-type fused filament fabrication (FFF) 3-D printing is a valuable tool for education. During FFF 3-D printing, thermal degradation of the polymer releases small particles and chemicals, many of which are hazardous to human health. In this study, particle and chemical emissions from 10 different filaments made from virgin (never printed) and recycled polymers were used to print the same object at the polymer manufacturer’s recommended nozzle temperature (“normal”) and at a temperature higher than recommended (“hot”) to simulate the real-world scenarios of a person intentionally or unknowingly printing on a machine with a changed setting. Emissions were evaluated in a college teaching laboratory using standard sampling and analytical methods. From mobility sizer measurements, particle number-based emission rates were 81 times higher; the proportion of ultrafine particles (diameter <100 nm) were 4% higher, and median particle sizes were a factor of 2 smaller for hot-temperature prints compared with normal-temperature prints (all p-values <0.05). There was no difference in emission characteristics between recycled and virgin acrylonitrile butadiene styrene and polylactic acid polymer filaments. Reducing contaminant release from FFF 3-D printers in educational settings can be achieved using the hierarchy of controls: (1) elimination/substitution (e.g., training students on principles of prevention-through-design, limiting the use of higher emitting polymer when possible); (2) engineering controls (e.g., using local exhaust ventilation to directly remove contaminants at the printer or isolating the printer from students); (3) administrative controls such as password protecting printer settings and establishing and enforcing adherence to a standard operating procedure based on a proper risk assessment for the setup and use (e.g., limiting the use of temperatures higher than those specified for the filaments used); and (4) maintenance of printers.