Protecting worker and public health involves an understanding of multiple determinants, including exposures to biological, chemical, or physical agents or stressors in combination with other determinants including type of employment, health status, and individual behaviors. This has been illustrated during the COVID-19 pandemic by increased exposure and health risks for essential workers and those with pre-existing conditions, and mask-wearing behavior. Health risk assessment practices for environmental and occupational health typically do not incorporate multiple stressors in combination with personal risk factors. While conceptual developments in cumulative risk assessment to inform a more holistic approach to these real-life conditions have progressed, gaps remain, and practical methods and applications are rare. This scoping review characterizes existing evidence of combined stressor exposures and personal factors and risk to foster methods for occupational cumulative risk assessment. The review found examples from many workplaces, such as manufacturing, offices, and health care; exposures to chemical, physical, and psychosocial stressors combined with modifiable and unmodifiable determinants of health; and outcomes including respiratory function and disease, cancers, cardio-metabolic diseases, and hearing loss, as well as increased fertility, menstrual dysfunction and worsened mental health. To protect workers, workplace exposures and modifiable and unmodifiable characteristics should be considered in risk assessment and management. Data on combination exposures can improve assessments and risk estimates and inform protective exposure limits and management strategies.

OBJECTIVE: Emergency management and operations (EMO) personnel require up-to-date information to make informed decisions during natural and man-made disasters. However, information gaps present challenges for accessing human health risk assessment and risk management strategies for dermal exposure. This article describes the development of a decision support system, the Dermal Exposure Risk Management and Logic (DERMaL) eToolkit. DESIGN: The DERMaL eToolkit provides information on key resources used in emergency incidents. Resources were classified according to response phase, resource categories, and information category and evaluated on reliability, accessibility, and preference by subject matter experts in emergency management fields. These rankings were used to generate a value of information score, unique for each resource, which aids in developing reference lists for users during each incident phase. RESULTS: This tool will identify and prioritize information resources on dermal risks, and can readily find the most relevant information to suit EMO needs. CONCLUSION: The DERMaL eToolkit can be used as an aid in finding information resources targeted to scenario-driven needs by providing well-vetted and prioritized resources related to dermal hazards, exposure, and risk assessments for EMO.

Multiple changes are influencing work, workplaces and workers in the US including shifts in the main types of work and the rise of the 'gig' economy. Work and workplace changes have coincided with a decline in unions and associated advocacy for improved safety and health conditions. Risk assessment has been the primary method to inform occupational and environmental health policy and management for many types of hazards. Although often focused on one hazard at a time, risk assessment frameworks and methods have advanced toward cumulative risk assessment recognizing that exposure to a single chemical or non-chemical stressor rarely occurs in isolation. We explore how applying cumulative risk approaches may change the roles of workers and employers as they pursue improved health and safety and elucidate some of the challenges and opportunities that might arise. Application of cumulative risk assessment should result in better understanding of complex exposures and health risks with the potential to inform more effective controls and improved safety and health risk management overall. Roles and responsibilities of both employers and workers are anticipated to change with potential for a greater burden of responsibility on workers to address risk factors both inside and outside the workplace that affect health at work. A range of policies, guidance and training have helped develop cumulative risk assessment for the environmental health field and similar approaches are available to foster the practice in occupational safety and health.

Uncertainties in understanding all potential modes-of-action for asthma induction and elicitation hinders design of hazard characterization and risk assessment methods that adequately screen and protect against hazardous chemical exposures. To address this challenge and identify current research needs, the University of Cincinnati and the American Cleaning Institute hosted a webinar series to discuss the current state-of-science regarding chemical-induced asthma. The general consensus is that the available database, comprised of data collected from routine clinical and validated toxicological tests, is inadequate for predicting or determining causal relationships between exposures and asthma induction for most allergens. More research is needed to understand the mechanism of asthma induction and elicitation in the context of specific chemical exposures and exposure patterns, and the impact of population variability and patient phenotypes. Validated tools to predict respiratory sensitization and to translate irritancy assays to asthma potency are needed, in addition to diagnostic biomarkers that assess and differentiate allergy versus irritant-based asthmatic responses. Diagnostic methods that encompass the diverse etiologies of asthmatic responses and incorporate robust exposure measurements capable of capturing different temporal patterns of complex chemical mixtures are needed. In the absence of ideal tools, risk assessors apply hazard-based safety assessment methods, in conjunction with active risk management, to limit potential asthma concerns, proactively identify new concerns, and ensure deployment of approaches to mitigate asthma-related risks.

Chemical allergens represent a significant health burden in the workplace. Exposures to such chemicals can cause the onset of a diverse group of adverse health effects triggered by immune-mediated responses. Common responses associated with workplace exposures to low molecular weight (LMW) chemical allergens range from allergic contact dermatitis to life-threatening cases of asthma. Establishing occupational exposure limits (OELs) for chemical allergens presents numerous difficulties for occupational hygiene professionals. Few OELs have been developed for LMW allergens because of the unique biological mechanisms that govern the immune-mediated responses. The purpose of this article is to explore the primary challenges confronting the establishment of OELs for LMW allergens. Specific topics include: (1) understanding the biology of LMW chemical allergies as it applies to setting OELs; (2) selecting the appropriate immune-mediated response (i.e., sensitization versus elicitation); (3) characterizing the dose (concentration)-response relationship of immune-mediated responses; (4) determining the impact of temporal exposure patterns (i.e., cumulative versus acute exposures); and (5) understanding the role of individual susceptibility and exposure route. Additional information is presented on the importance of using alternative exposure recommendations and risk management practices, including medical surveillance, to aid in protecting workers from exposures to LMW allergens when OELs cannot be established.

Occupational exposure limits have traditionally focused on preventing morbidity and mortality arising from inhalation exposures to individual chemical stressors in the workplace. While central to occupational risk assessment, occupational exposure limits have limited application as a refined disease prevention tool because they do not account for all of the complexities of the work and non-occupational environments and are based on varying health endpoints. To be of greater utility, occupational exposure limits and other risk management tools could integrate broader consideration of risks from multiple exposure pathways and routes (aggregate risk) as well as the combined risk from exposure to both chemical and non-chemical stressors, within and beyond the workplace, including the possibility that such exposures may cause interactions or modify the toxic effects observed (cumulative risk). Although still at a rudimentary stage in many cases, a variety of methods and tools have been developed or are being used in allied risk assessment fields to incorporate such considerations in the risk assessment process. These approaches, which are collectively referred to as cumulative risk assessment, have potential to be adapted or modified for occupational scenarios and provide a tangible path forward for occupational risk assessment. Accounting for complex exposures in the workplace and the broader risks faced by the individual also requires a more complete consideration of the composite effects of occupational and non-occupational risk factors to fully assess and manage worker health problems. Barriers to integrating these different factors remain, but new and ongoing community-based and worker health-related initiatives may provide mechanisms for identifying and integrating risk from aggregate exposures and cumulative risks from all relevant sources, be they occupational or non-occupational.

Emergency Management and Operations (EMO) personnel are in need of resources and tools to assist in understanding the health risks associated with dermal exposures during chemical incidents. This article reviews available resources and presents a conceptual framework for a decision support system (DSS) that assists in characterizing and managing risk during chemical emergencies involving dermal exposures. The framework merges principles of three decision-making techniques: 1) scenario planning, 2) risk analysis, and 3) multicriteria decision analysis (MCDA). This DSS facilitates dynamic decision making during each of the distinct life cycle phases of an emergency incident (ie, preparedness, response, or recovery) and identifies EMO needs. A checklist tool provides key questions intended to guide users through the complexities of conducting a dermal risk assessment. The questions define the scope of the framework for resource identification and application to support decision-making needs. The framework consists of three primary modules: 1) resource compilation, 2) prioritization, and 3) decision. The modules systematically identify, organize, and rank relevant information resources relating to the hazards of dermal exposures to chemicals and risk management strategies. Each module is subdivided into critical elements designed to further delineate the resources based on relevant incident phase and type of information. The DSS framework provides a much needed structure based on contemporary decision analysis principles for 1) documenting key questions for EMO problem formulation and 2) a method for systematically organizing, screening, and prioritizing information resources on dermal hazards, exposures, risk characterization, and management.

The goal of these studies was to measure and interpret the skin permeability characteristics of 2-hydroxypropyl acrylate (HPA) as a model compound that is completely miscible with water. METHODS: In vitro permeation from HPA-H2O binary mixtures through human epidermis and silicone membranes was measured. Thermodynamic activities of HPA and H2O in these mixtures were determined. Permeation was also measured through epidermis and silicone from donor solutions with constant HPA activity but different H2O activities. Water uptake into desiccated human stratum corneum (SC) equilibrated with HPA-H2O mixtures was determined. RESULTS: Steady-state flux of HPA through silicone was a linear function of HPA activity but not HPA concentration. For epidermis on the other hand, flux increased with HPA activity only for HPA activities ≤ 0.35. At constant HPA activity, flux decreased 4.5-fold as water activity decreased from 1 to 0.8. Incubation of SC with HPA-H2O mixtures resulted in substantial changes in SC water content, dependent on the water activity of the mixture and consistent with measured SC water sorption data. CONCLUSIONS: These experiments provide unequivocal evidence of a substantial increase in epidermal barrier function resulting from SC dehydration. Dehydration-related alterations in the SC appear responsible for the observed flux characteristics.

A common dermal exposure assessment strategy estimates the systemic uptake of chemical in contact with skin using the fixed fractional absorption approach: the dermal absorbed dose is estimated as the product of exposure and the fraction of applied chemical that is absorbed, assumed constant for a given chemical. Despite the prominence of this approach there is little guidance regarding the evaluation of experiments from which fractional absorption data are measured. An analysis of these experiments is presented herein, and limitations to the fixed fractional absorption approach are discussed. The analysis provides a set of simple algebraic expressions that may be used in the evaluation of finite dose dermal absorption experiments, affording a more data-driven approach to dermal exposure assessment. Case studies are presented that demonstrate the application of these tools to the assessment of dermal absorption data. (Journal of Exposure Science and Environmental Epidemiology advance online publication, 29 May 2013; doi:10.1038/jes.2013.23.)

With increasing numbers and quantities of chemicals in commerce and use, scientific attention continues to focus on the environmental and public health consequences of chemical production processes and exposures. Concerns about environmental stewardship have been gaining broader traction through emphases on sustainability and "green chemistry" principles. Occupational safety and health has not been fully promoted as a component of environmental sustainability. However, there is a natural convergence of green chemistry/sustainability and occupational safety and health efforts. Addressing both together can have a synergistic effect. Failure to promote this convergence could lead to increasing worker hazards and lack of support for sustainability efforts. The National Institute for Occupational Safety and Health has made a concerted effort involving multiple stakeholders to anticipate and identify potential hazards associated with sustainable practices and green jobs for workers. Examples of potential hazards are presented in case studies with suggested solutions such as implementing the hierarchy of controls and prevention through design principles in green chemistry and green building practices. Practical considerations and strategies for green chemistry, and environmental stewardship could benefit from the incorporation of occupational safety and health concepts which in turn protect affected workers.

The disaster environment frequently presents rapidly evolving and unpredictable hazardous exposures to emergency responders. Improved estimates of exposure and effect from biomonitoring can be used to assess exposure-response relationships, potential health consequences, and effectiveness of control measures. Disaster settings, however, pose significant challenges for biomonitoring. A decision process for determining when to conduct biomonitoring during and following disasters was developed. Separate but overlapping decision processes were developed for biomonitoring performed as part of occupational health investigations that directly benefit emergency responders in the short term and for biomonitoring intended to support research studies. Two categories of factors critical to the decision process for biomonitoring were identified: Is biomonitoring appropriate for the intended purpose and is biomonitoring feasible under the circumstances of the emergency response? Factors within these categories include information needs, relevance, interpretability, ethics, methodology, and logistics. Biomonitoring of emergency responders can be a valuable tool for exposure and risk assessment. Information needs, relevance, and interpretability will largely determine if biomonitoring is appropriate; logistical factors will largely determine if biomonitoring is feasible. The decision process should be formalized and may benefit from advance planning.

Human health risk assessments continue to evolve and now focus on the need for cumulative risk assessment (CRA). CRA involves assessing the combined risk from coexposure to multiple chemical and nonchemical stressors for varying health effects. CRAs are broader in scope than traditional chemical risk assessments because they allow for a more comprehensive evaluation of the interaction between different stressors and their combined impact on human health. Future directions of CRA include greater emphasis on local-level community-based assessments; integrating environmental, occupational, community, and individual risk factors; and identifying and implementing common frameworks and risk metrics for incorporating multiple stressors.

Risk is an inherent aspect of our lives. Whether the topic is the nation's dietary habits, community air pollution or chemical exposures in the workplace, risk analysis is an integral part of the conversation. | Risk analysis is the combined activities of assessing, managing and communicating human health risks. Interest in understanding risk from chemical exposures and other stressors has led to the formalization of health risk assessment as an applied public health science. Numerous seminal reports from the National Academies of Science (NAS) have highlighted the framework for risk assessment and risk management, as well as key changes within the practice of risk analysis. | The profession of industrial hygiene has evolved to reflect the changes in health risk assessment methodology and practice. Traditional industrial hygiene practice−the anticipation, recognition, evaluation and control of occupational and environmental hazards and risks–parallels key aspects of health risk assessment. Thus, industrial hygienists have a strong history as leading practitioners of all aspects of risk analysis–health risk assessment, risk management and risk communication–within the occupational environment.

For more than three decades, health practitioners and regulatory agencies have used risk assessment methods to characterize health risks. Risk assessment is the process of determining the likelihood and severity of health risk to an individual or population from exposure to a chemical or other stressor. Evolving methods and advances in science and technology offer several opportunities for improving risk assessment and its application to occupational settings.

1-Bromopropane (1-BP; CAS number 106-94-5), also known as n-propyl bromide, is a halogenated short-chain alkane used as an organic solvent with numerous commercial and industrial applications, including garment dry cleaning and vapor degreasing of metals. The purpose of this study was to determine the dermal absorption characteristics and corrosivity of 1-BP. Heat-separated human epidermal membranes were mounted on static diffusion cells. Different exposure scenarios were studied (infinite dose, finite dose, and transient exposure) using neat 1-BP and saturated aqueous solution as donor. Steady-state fluxes for infinite-dose neat 1-BP exposure averaged 625 to 960 mcg cm(-2) h(-1). The finite-dose (10 mcl/cm(2) = 13.5 mg/cm(2)) unoccluded donor resulted in penetration of <0.2% of the applied dose (22 mcg/cm(2)). A 10-min transient exposure to infinite dose resulted in total penetration of 179 mcg/cm(2). Steady-state 1-BP fluxes from neat application of a commercial dry cleaning solvent were similar (441 to 722 mcg cm(-2) h(-1)). The permeability coefficient of 1-BP in water vehicle was 0.257 +/- 0.141 cm/h. The absorption potential of 1-BP following dermal exposure is dependent upon the type and duration of exposure. Donor losses due to evaporation were approximately 500-fold greater than dermal absorption flux; evaporation flux was 420 mg cm(-2) h(-1). 1-BP is cytotoxic but not corrosive, based on results from a cultured reconstructed human epidermal model (EpiDerm Skin Corrosivity Test).

Skin notations (SNs) represent a hazard characterization tool for alerting workers of health hazards associated with dermal contact with chemicals. This study evaluated the efficacy of a predictive model utilized by the National Institute for Occupational Safety and Health to identify dermal hazards based on potential of systemic absorption compared to hazard assignments based on dermal lethal dose 50% or logarithm of octanol-water partition coefficient. A total of 480 chemicals assigned an SN from at least one of seven institutes were selected and partitioned into seven hazard categories by frequency of SN assignment to provide a basis of evaluation for the predictivity of the examined criteria. We find that all three properties serve as a qualitative indicator in support of a dichotomous decision on dermal hazard; the predictive modeling was identified from a multiple regression analysis as the most significant indicator. The model generated estimates that corresponded to anticipated hazard potentials, suggesting a role of the model to further serve as a hazard-ranking tool. The hazard-ranking capability of the model was consistent with the scheme of acute toxicity classification in the Globally Harmonized System of Classification and Labeling of Chemicals.

This article presents an overview of a strategy for assignment of hazard-specific skin notations (SK), developed by the National Institute for Occupational Safety and Health (NIOSH). This health hazard characterization strategy relies on multiple SKs capable of delineating systemic (SYS), direct (DIR), and immune-mediated (SEN) adverse effects caused by dermal exposures to chemicals. One advantage of the NIOSH strategy is the ability to combine SKs when it is determined that a chemical may cause multiple adverse effects following dermal contact (e.g., SK: SYS-DIR-SEN). Assignment of the SKs is based on a weight-of-evidence (WOE) approach, which refers to the critical examination of all available data from diverse lines of evidence and the derivation of a scientific interpretation based on the collective body of data including its relevance, quality, and reported results. Numeric cutoff values, based on indices of toxic potency, serve as guidelines to aid in consistently determining a chemical's relative toxicity and hazard potential. The NIOSH strategy documents the scientific rationale for determination of the hazard potential of a chemical and the subsequent assignment of SKs. A case study of acrylamide is presented as an application of the NIOSH strategy.