Biological monitoring to assess exposure to diisocyanates in the workplace is becoming increasingly widespread due to its relative ease of use and ability to look at all exposure routes. Currently, biological monitoring measures the corresponding isocyanate-derived diamine in urine, after hydrolysis. Because of this, any exposure to the diamines themselves released during the industrial process could confound the assessment of diisocyanate exposure. This paper reports an initial assessment of the extent of diamine formation and exposure during different processes involving diisocyanates including casting, grouting, core making, spray painting, foam blowing, and floor screeding. Air monitoring and glove analysis were conducted for both the relevant diisocyanate (measured as total NCO) and its corresponding diamine; urine samples were analysed (after hydrolysis) for the isocyanate-derived diamine. Processes that generated aerosols (as demonstrated by impinger analysis) such as spray painting and foam blowing were associated with the detection of diamines. Those processes that did not generate aerosols (casting, grouting, core making, and screeding) had no diamines detected, either in air or on gloves. In spray-painting tasks, diamines were a minor component (<15%) of the ambient concentration whereas in the foam blowing processes, where water is added to the process, diamine generation is more marked (up to eight times the airborne NCO concentration). Some non-aerosol processes gave rise to substantial diamine levels in urine (in exceedance of international guidance values, >5 µmol mol-1 creatinine) despite airborne levels being well within occupational exposure limits (20 µg m-3 total NCO in Great Britain); measurement data and statistical modelling indicated that skin absorption was the most likely exposure route. Foam blowing exposures were more complex, but urinary levels were greater than those expected from diisocyanate inhalation alone (measured as total NCO). This study provides evidence that biological monitoring for diisocyanates based on measuring the corresponding diamine in urine is valid, although any co-exposure to diamines themselves should be considered when interpreting results. It also demonstrates the potential for substantial skin absorption of diisocyanates in certain processes such as floor screeding and foam production.

No abstract

Workers in the electroplating industry are potentially exposed to a range of hazardous substances including nickel and hexavalent chromium (chromium VI) compounds. These can cause serious health effects, including cancer, asthma and dermatitis. This research aimed to investigate whether repeat biological monitoring (BM) over time could drive sustainable improvements in exposure control in the industry. BM was performed on multiple occasions over 3 years, at 53 electroplating companies in Great Britain. Surface and dermal contamination was also measured, and controls were assessed. Air monitoring was undertaken on repeat visits where previous BM results were of concern. There were significant reductions in urinary nickel and chromium levels over the lifetime of this work in the subset of companies where initially, control deficiencies were more significant. Increased risk awareness following provision of direct feedback to individual workers and targeted advice to companies is likely to have contributed to these reductions. This study has shown that exposures to chromium VI and nickel in the electroplating industry occur via a combination of inhalation, dermal and ingestion routes. Surface contamination found in areas such as canteens highlights the potential for transferral from work areas, and the importance of a regular cleaning regime.

Preventing SARS-CoV-2 transmission and protecting people from COVID-19 is the most significant public health challenge faced in recent years. COVID-19 outbreaks are occurring in workplaces and evidence is needed to support effective strategies to prevent and control these outbreaks. Investigations into these outbreaks are routinely undertaken by public health bodies and regulators in the United Kingdom (UK); however, such investigations are typically disparate in nature with a lack of consistency across all investigations, preventing meaningful analysis of the data collected. The COVID-OUT (COVID-19 Outbreak investigation to Understand Transmission) study aims to collect a consistent set of data in a systematic way from workplaces that are experiencing outbreaks, to understand SARS-CoV-2 transmission risk factors, transmission routes, and the role they play in the COVID-19 outbreaks. Suitable outbreak sites are identified from public health bodies. Following employer consent to participate, the study will recruit workers from workplaces where there are active outbreaks. The study will utilise data already collected as part of routine public health outbreak investigations and collect additional data through a comprehensive questionnaire, viral and serologic testing of workers, surface sampling, viral genome sequencing, and an environmental assessment of building plans, ventilation and current control measures. At each site, a detailed investigation will be carried out to evaluate transmission routes. A case-control approach will be used to compare workers who have and have not had SARS-CoV-2 infections during the outbreak period to assess transmission risk factors. Data from different outbreaks will be combined for pooled analyses to identify common risk factors, as well as factors that differ between outbreaks. The COVID-OUT study can contribute to a better understanding of why COVID-19 outbreaks associated with workplaces occur and how to prevent these outbreaks from happening in the future.

No abstract