Cancer incidence amongst UK firefighters.

Firefighters suffer an increased risk of cancer from exposures to chemicals released from fires. Our earlier research has found that fire toxicants not only remain on firefighters' PPE, but are also tracked back to fire stations. The UK Firefighter Contamination Survey assesses firefighters' risk of developing cancer due to occupational exposure to fire toxins. Over 4% of surveyed firefighters were found to have a cancer diagnosis, with the age-specific cancer rate up to 323% higher (35-39 year olds) than that of the general population. Firefighters who had served ≥ 15 years were 1.7 times more likely to develop cancer than those who had served less time. Firefighters were at least twice as likely to be diagnosed with cancer if they noticed soot in their nose/throat (odds ratio (OR) = 2.0, 1.1-3.5), or remained in their PPE for more than four hours after attending a fire incident (OR = 2.3, 1.1-5.2). Also associated with an increased likelihood of cancer was: eating while wearing PPE (OR = 1.8, 1.2-2.7); failing to store clean/dirty PPE separately (OR = 1.3, 1.0-1.7); working in a station that smells of fire (OR = 1.3, 1.0-1.8) or not having designated (separated) clean and dirty areas (OR = 1.4, 1.1-1.7); using an on-site washing machine to launder fire hoods (OR = 1.3, 1.0-1.7); feeling that cleaning is not taken seriously at work (OR = 1.5, 1.2-2.0).

Culture and awareness of occupational health risks amongst UK firefighters.

Firefighters are exposed to toxic chemicals not only from the fire incidents they attend, but also from their contaminated station and/or personal protective equipment (PPE). Little is currently known about firefighters' awareness, attitudes, and behaviours towards contaminants which was assessed in the UK firefighter contamination survey. Results revealed that lack of training on fire effluents and their health outcomes are strongly associated with increased fire smoke/contaminant exposure. Notably, untrained firefighters were at least twice as likely to: never clean personal protective equipment (PPE) (Crude Odds Ratio, OR 2.0, 1.5-2.7), infrequently send their PPE for professional cleaning (OR 2.0, 1.6-2.4), remain in the workwear (t-shirt etc.) worn while attending a fire incident (OR up to 3.6, 2.3-5.6), and indicate that cleaning at fire stations is not taken seriously (OR 2.4, 2.2-2.6). Firefighters personally viewing contamination as a "badge of honour" (BoH) were at least twice as likely to: remain in contaminated PPE after fire incidents (OR 2.3, 1.4-3.9), eat with sooty hands (OR 2.2, 1.9-2.5), notice soot in the nose/throat (OR 3.7, 2.7-5.2), and smell fire smoke on the body for more than a day after incidents (OR 2.0, 1.6-2.4). They were also more likely to indicate that cleaning at fire stations is not taken seriously (OR 2.5, 2.2-2.9) and that fire stations smell of smoke always/most of the time (OR 2.3, 2.0-2.6). Strong links were also found between belief in the BoH and never cleaning PPE (OR 1.9, 1.4-2.7), and eating while wearing contaminated PPE (OR 1.8, 1.5-2.2).

Contamination of UK firefighters personal protective equipment and workplaces.

Firefighters' personal protective equipment (PPE) is a potential source of chronic exposure to toxic contaminants commonly released from fires. These contaminants have also been found in fire stations. However, little research characterises the routes via which fire contaminants travel back to fire stations. The UK Firefighter Contamination Survey provides information on firefighters' PPE provision, decontamination, and storage practices. All serving UK firefighters were eligible to take part in the survey, which comprised 64 questions. A total of 10,649 responses were included for analysis, accounting for roughly 24% of the UK's firefighting workforce. Results revealed that most firefighters (84%) de-robe contaminated PPE/workwear after re-entering the appliance cab. There was a significant decreasing tendency to send PPE for cleaning after every incident with increasing seniority of role, length of service, and fire attendance frequency. Around one third of firefighters cleaned PPE after every incident. A number of issues were linked to external professional cleaning services, e.g. shrinkage, fit, turn-around time, and stock of reserve/pooled PPE. PPE storage was found to be a potential source of cross contamination, with almost half of firefighters (45%) indicating clean and dirty PPE is not stored separately. More than half of firefighters (57%) stored fire gloves (an item sent for professional decontamination by only 19% of firefighters, and never cleaned by 20%) within other items of PPE such as helmets, boots and tunic/trouser pockets. The survey's results can be used to target gaps in decontamination measures within UK Fire and Rescue Services.

Mental health of UK firefighters.

Exposure to trauma, high-stress situations, and disrupted sleep are well known risk factors affecting firefighters' mental health. Little is known about the association between firefighters' exposure to fire contaminants and mental health disorders. The UK Firefighter Contamination Survey assessed firefighters' health and capacity for occupational exposure to contaminants. Participants were invited to anonymously complete its 64 questions online. Logistic regression analyses assessed the associations between self-reported mental health disorders and proxies of contaminant exposure. Results found that firefighters who notice soot in their nose/throat for more than a day after attending fires (Odds Ratio (OR) = 1.8, 1.4-2.4), and those who remain in their personal protective equipment (PPE) for over 4 h after fires (OR = 1.9, 1.2-3.1), were nearly twice as likely to report mental health disorders. Significantly increased odds ratios for all three outcomes of interest (anxiety, depression and/or any mental health disorders) were also found among firefighters who take PPE home to clean. Sleeping problems were reported by 61% of firefighters. These firefighters were 4.2 times more likely to report any mental health disorder (OR = 4.2, 3.7-4.9), 2.9 times more likely to report anxiety (OR = 2.9, 2.4-3.5) and 2.3 times more likely to report depression (OR = 2.3, 1.9-2.8) when compared to firefighters who did not report sleep issues. Effective decontamination measures within UK Fire and Rescue Services, together with firefighters' wellness, may play a crucial role in protecting firefighters' mental health.

The PFAS-Tox Database: A systematic evidence map of health studies on 29 per- and polyfluoroalkyl substances.

BACKGROUND: PFAS (per-and polyfluoroalkyl substances) are a large class of synthetic chemicals widely used in consumer products and industrial processes. The scientific literature on PFAS has increased dramatically in the last decade. Many stakeholders, including regulators, scientists, non-governmental organizations, and concerned individuals could benefit from an efficient way to access the health and toxicological literature related to PFAS. OBJECTIVE: To create a systematic evidence map of the available peer-reviewed health or toxicological research for 29 PFAS. METHODS: A protocol for conducting this systematic evidence map was initially published on Zenodo (Pelch et al. 2019c), then peer reviewed and published in Environment International (Pelch et al. 2019d). PubMed database was searched through January 25, 2021. Studies were screened for inclusion and exclusion according to the Populations, Exposures, Comparators, and Outcomes (PECO) statement. Inclusion criteria were intentionally broad and included any human, animal, and/or in vitro study that investigated exposure to one of the 29 PFAS of interest and a human health or toxicological effect. Selected study details were extracted from included studies as described in the protocol. Study appraisal was not conducted. The included studies and extracted meta-data are freely available in the online, interactive systematic evidence map at https://pfastoxdatabase.org. RESULTS: Over 15,000 studies were retrieved from the PubMed literature searches. After manual screening, 1,067 studies were identified and included as investigating the health or toxicological effect of one or more PFAS of interest. There were 505 human, 385 animal, and 220 in vitro studies. Summary tables of the extracted data and overall observations are included in this report. CONCLUSIONS: The PFAS-Tox Database is a useful tool for searching, filtering, and identifying peer reviewed research on the health and toxicological effects of the included PFAS. In this summary of the evidence map we provide examples of data gaps and clusters revealed by the database, with the goal of helping direct future research efforts, facilitate systematic reviews (e.g. on immune effects, mixtures of PFAS, or effects of short chain PFAS), inform regulatory risk assessments, and improve opportunities for cross-disciplinary coordination. We also discuss how this tool supports scientists, regulatory agencies, and other individuals by increasing awareness and access to current evidence regarding the health effects associated with PFAS exposure.

Knowledge Organization Systems for Systematic Chemical Assessments.

BACKGROUND: Although the implementation of systematic review and evidence mapping methods stands to improve the transparency and accuracy of chemical assessments, they also accentuate the challenges that assessors face in ensuring they have located and included all the evidence that is relevant to evaluating the potential health effects an exposure might be causing. This challenge of information retrieval can be characterized in terms of "semantic" and "conceptual" factors that render chemical assessments vulnerable to the streetlight effect. OBJECTIVES: This commentary presents how controlled vocabularies, thesauruses, and ontologies contribute to overcoming the streetlight effect in information retrieval, making up the key components of Knowledge Organization Systems (KOSs) that enable more systematic access to assessment-relevant information than is currently achievable. The concept of Adverse Outcome Pathways is used to illustrate what a general KOS for use in chemical assessment could look like. DISCUSSION: Ontologies are an underexploited element of effective knowledge organization in the environmental health sciences. Agreeing on and implementing ontologies in chemical assessment is a complex but tractable process with four fundamental steps. Successful implementation of ontologies would not only make currently fragmented information about health risks from chemical exposures vastly more accessible, it could ultimately enable computational methods for chemical assessment that can take advantage of the full richness of data described in natural language in primary studies. https://doi.org/10.1289/EHP6994.

Recommendations for the conduct of systematic reviews in toxicology and environmental health research (COSTER).

BACKGROUND: There are several standards that offer explicit guidance on good practice in systematic reviews (SRs) for the medical sciences; however, no similarly comprehensive set of recommendations has been published for SRs that focus on human health risks posed by exposure to environmental challenges, chemical or otherwise. OBJECTIVES: To develop an expert, cross-sector consensus view on a key set of recommended practices for the planning and conduct of SRs in the environmental health sciences. METHODS: A draft set of recommendations was derived from two existing standards for SRs in biomedicine and developed in a consensus process, which engaged international participation from government, industry, non-government organisations, and academia. The consensus process consisted of a workshop, follow-up webinars, email discussion and bilateral phone calls. RESULTS: The Conduct of Systematic Reviews in Toxicology and Environmental Health Research (COSTER) recommendations cover 70 SR practices across eight performance domains. Detailed explanations for specific recommendations are made for those identified by the authors as either being novel to SR in general, specific to the environmental health SR context, or potentially controversial to environmental health SR stakeholders. DISCUSSION: COSTER provides a set of recommendations that should facilitate the production of credible, high-value SRs of environmental health evidence, and advance discussion of a number of controversial aspects of conduct of EH SRs. Key recommendations include the management of conflicts of interest, handling of grey literature, and protocol registration and publication. A process for advancing from COSTER's recommendations to developing a formal standard for EH SRs is also indicated.

A Survey of Systematic Evidence Mapping Practice and the Case for Knowledge Graphs in Environmental Health and Toxicology.

Systematic evidence mapping offers a robust and transparent methodology for facilitating evidence-based approaches to decision-making in chemicals policy and wider environmental health (EH). Interest in the methodology is growing; however, its application in EH is still novel. To facilitate the production of effective systematic evidence maps for EH use cases, we survey the successful application of evidence mapping in other fields where the methodology is more established. Focusing on issues of "data storage technology," "data integrity," "data accessibility," and "transparency," we characterize current evidence mapping practice and critically review its potential value for EH contexts. We note that rigid, flat data tables and schema-first approaches dominate current mapping methods and highlight how this practice is ill-suited to the highly connected, heterogeneous, and complex nature of EH data. We propose this challenge is overcome by storing and structuring data as "knowledge graphs." Knowledge graphs offer a flexible, schemaless, and scalable model for systematically mapping the EH literature. Associated technologies, such as ontologies, are well-suited to the long-term goals of systematic mapping methodology in promoting resource-efficient access to the wider EH evidence base. Several graph storage implementations are readily available, with a variety of proven use cases in other fields. Thus, developing and adapting systematic evidence mapping for EH should utilize these graph-based resources to ensure the production of scalable, interoperable, and robust maps to aid decision-making processes in chemicals policy and wider EH.

PFAS health effects database: Protocol for a systematic evidence map.

BACKGROUND: Per- and polyfluoroalkyl substances (PFAS) confer waterproof, greaseproof, and non-stick properties when added to consumer products. They are also used for industrial purposes including in aqueous film forming foams for firefighting. PFAS are ubiquitous in the environment, are widely detected in human biomonitoring studies, and are of growing regulatory concern across federal, state, and local governments. Regulators, scientists, and citizens need to stay informed on the growing health and toxicology literature related to PFAS. OBJECTIVES: The goal of this systematic evidence map is to identify and organize the available health and toxicology related literature on a set of 29 PFAS of emerging and growing concern. SEARCH AND STUDY ELIGIBILITY: We will search the electronic database PubMed for health or toxicological studies on 29 PFAS of emerging concern. Eligible studies must contain primary research investigating the link between one or more of the PFAS of interest and a health effect, toxicological, or biological mechanistic endpoint. STUDY APPRAISAL AND SYNTHESIS METHODS: Title and abstract screening and full text review will require a single reviewer for inclusion to the next level and two independent reviewers for exclusion. Study quality will not be conducted for this evidence mapping. Study characteristics will be extracted and coded from the included studies and checked for accuracy by a second reviewer. The extracted and coded information will be visualized in a publicly available, interactive database hosted on Tableau Public. Results of the evidence mapping will be published in a narrative summary.

Systematic evidence maps as a novel tool to support evidence-based decision-making in chemicals policy and risk management.

BACKGROUND: While systematic review (SR) methods are gaining traction as a method for providing a reliable summary of existing evidence for health risks posed by exposure to chemical substances, it is becoming clear that their value is restricted to a specific range of risk management scenarios - in particular, those which can be addressed with tightly focused questions and can accommodate the time and resource requirements of a systematic evidence synthesis. METHODS: The concept of a systematic evidence map (SEM) is defined and contrasted to the function and limitations of systematic review (SR) in the context of risk management decision-making. The potential for SEMs to facilitate evidence-based decision-making are explored using a hypothetical example in risk management priority-setting. The potential role of SEMs in reference to broader risk management workflows is characterised. RESULTS: SEMs are databases of systematically gathered research which characterise broad features of the evidence base. Although not intended to substitute for the evidence synthesis element of systematic reviews, SEMs provide a comprehensive, queryable summary of a large body of policy relevant research. They provide an evidence-based approach to characterising the extent of available evidence and support forward looking predictions or trendspotting in the chemical risk sciences. In particular, SEMs facilitate the identification of related bodies of decision critical chemical risk information which could be further analysed using SR methods, and highlight gaps in the evidence which could be addressed with additional primary studies to reduce uncertainties in decision-making. CONCLUSIONS: SEMs have strong and growing potential as a high value tool in resource efficient use of existing research in chemical risk management. They can be used as a critical precursor to efficient deployment of high quality SR methods for characterising chemical health risks. Furthermore, SEMs have potential, at a large scale, to support the sort of evidence summarisation and surveillance methods which would greatly increase the resource efficiency, transparency and effectiveness of regulatory initiatives such as EU REACH and US TSCA.