Firefighter exposures to organic and inorganic gas emissions in emergency residential and industrial fires

Hand eczema and skin complaints in particulate matter-exposed occupations - firefighters, chimney sweepers, and ferrosilicon smelter workers in Norway

BACKGROUND

The objective was to investigate self-reported hand eczema, and skin complaints at other skin locations among workers exposed to particulate matter, especially ultrafine particles.

METHOD

We conducted a cross-sectional study on workers from one ferro-silicon smelter plant, eight chimney sweeper stations and one firefighter station across Norway. Participants answered an extended version of the Nordic Occupational Skin Questionnaire (NOSQ-2022), with additional questions about whole-body skin complaints and visible dust deposition. Results are presented as descriptive data using firefighters as reference group. Odds ratio (OR) was calculated using logistic regression on lifetime prevalence of hand eczema adjusted for potential confounders and mediators. P-values were calculated using likelihood ratio test against the crude OR.

RESULTS

A total of 186 participants answered the questionnaire: 74 chimney sweepers, 52 firefighters and 60 smelter workers. Participation rate was 95.0, 94.5 and 63.6%, respectively. Lifetime prevalence of hand eczema was 9.5, 9.6, and 28.3%, respectively. The point prevalence of hand eczema was 1.4, 1.9 and 10.0%, respectively. We estimated OR for lifetime hand eczema in smelter workers to 4.36 [95% CI: 1.31-14.43, p = 0.016] and for lifetime skin complaints in other locations to 2.25 [95% CI: 0.98-5.18, p = 0.058]. The lifetime prevalence of skin complaints at other locations was 18.9, 23.1 and 40.0%, respectively. The point prevalence was 14.9, 9.6 and 16.7%, respectively. These estimates were not statistically significant but indicates that smelter workers have more skin complaints also at other locations.

CONCLUSION

This study reports a more than four-fold increased risk of hand eczema in smelter workers, and possibly a higher risk of skin complaints in other body locations, compared to the other occupations. Longitudinal studies with larger population are needed to verify the marked increased risk of eczema among smelters and establish causation.

Off-gassing from firefighter suits (nomex) as an indoor source of BTEXS

The clothes and special equipment of firefighters can be a source of indoor air pollution. Nevertheless, it has not been investigated so far what the scale of the release of various compounds from such materials into the indoor air can be. The following study analysed the results of an experiment involving the passive measurement of concentrations of selected compounds, i.a. benzene, toluene, ethylbenzene, m,p-xylene, o-xylene, styrene, isopropylbenzene and n-propylbenzene (BTEXS) in the air of a room where firefighters' special clothing, which had been previously exposed to emissions from simulated fires, was stored. The study included simulations of fires involving three materials: wood, processed wood (OSB/fibreboard) and a mixture of plastics. After being exposed to the simulated fire environment, special clothing (so-called nomex) was placed in a sealed chamber, where passive collection of BTEXS was carried out using tube-type axial passive samplers and a gas chromatograph. Irrespective of which burned material special clothing was exposed to, the compound emitted into the air most intensively was toluene. Its rate of release from a single nomex ranges from 4.4 to 28.6 μg h-1, while the corresponding rates for the sum of BTEXS are between 9.97 and 44.29 μg h-1.

Air pollution inside fire stations: State-of-the-art and future challenges

Firefighters are frequently exposed to products of combustion and pyrolysis. Exposure to these substances occurs not only during fires but also at fire stations, particularly where fire equipment and fire uniforms are stored after firefighting operations. The aims of this study were to review the research on the concentrations of various air pollutants in fire stations, identify the limitations and strengths of such research, identify research gaps and related future challenges, and highlight potential solutions for reducing firefighter exposure to air pollution at fire stations. A total of 32 articles published in international journals during 1987-2023 were selected for analysis. The most frequently studied pollutants in fire stations were polycyclic aromatic hydrocarbons, particulate matter, and diesel particulate matter. Research was most often conducted on changing rooms and garages. Firefighting equipment, personal protective equipment, fire trucks, and combustion tools were identified as the main sources of pollution at fire stations. Recommendations aimed at reducing the concentration of pollutants in fire stations were mainly concerned with the systematic decontamination of equipment and the introduction of ventilation solutions that would remove exhaust fumes from garages. This in-depth literature review indicates a lack of comprehensive research on the state and quality of air at fire stations. It also highlights the emerging need for more knowledge on the concentrations of air pollutants in fire stations, health exposure related to these substances, and an analysis of the effectiveness of the proposed solutions.

Biomonitoring of firefighting forces: a review on biomarkers of exposure to health-relevant pollutants released from fires

Occupational exposure as a firefighter has recently been classified as a carcinogen to humans by International Agency for Research on Cancer (IARC). Biomonitoring has been increasingly used to characterize exposure of firefighting forces to contaminants. However, available data are dispersed and information on the most relevant and promising biomarkers in this context of firefighting is missing. This review presents a comprehensive summary and critical appraisal of existing biomarkers of exposure including volatile organic compounds such as polycyclic aromatic hydrocarbons, several other persistent other organic pollutants as well as heavy metals and metalloids detected in biological fluids of firefighters attending different fire scenarios. Urine was the most characterized matrix, followed by blood. Firefighters exhaled breath and saliva were poorly evaluated. Overall, biological levels of compounds were predominantly increased in firefighters after participation in firefighting activities. Biomonitoring studies combining different biomarkers of exposure and of effect are currently limited but exploratory findings are of high interest. However, biomonitoring still has some unresolved major limitations since reference or recommended values are not yet established for most biomarkers. In addition, half-lives values for most of the biomarkers have thus far not been defined, which significantly hampers the design of studies. These limitations need to be tackled urgently to improve risk assessment and support implementation of better more effective preventive strategies.

Quantification of Elevated Hydrogen Cyanide (HCN) Concentration Typical in a Residential Fire Environment Using Mid-IR Tunable Diode Laser

A versatile portable tunable diode laser based measurement system for measuring elevated concentrations of hydrogen cyanide (HCN) in a time-resolved manner is developed for application in the fire environment. The direct absorption tunable diode laser spectroscopy (DA-TDLAS) technique is employed using the R11 absorption line centered at 3345.3 cm^-1 (2989.27 nm) in the fundamental C-H stretching band (ν₁) of the HCN absorption spectrum. The measurement system is validated using calibration gas of known HCN concentration and the relative uncertainty in measurement of HCN concentration is 4.1% at 1500 ppm. HCN concentration is measured with a sampling frequency of 1 Hz, in gas sampled from 1.5 m, 0.9 m, and 0.3 m heights in the Fireground Exposure Simulator (FES) prop at the University of Illinois Fire Service Institute, Champaign, Illinois. The immediately dangerous to life and health (IDLH) concentration of 50 parts per million (ppm) is exceeded at all the three sampling heights. A maximum concentration of 295 ppm is measured at the 1.5 m height. The HCN measurement system, expanded to measure HCN simultaneously from two sampling locations, is then deployed in two full-scale experiments designed to simulate a realistic residential fire environment at the Delaware County Emergency Services Training Center, Sharon Hill, Pennsylvania.

The effect of blood cadmium levels on hypertension in male firefighters in a metropolitan city

Background

This study investigated the effect of dispatch frequency on blood cadmium levels and the effect of blood cadmium levels on hypertension in male firefighters in a metropolitan city.

Methods

We conducted a retrospective longitudinal study of male firefighters who completed the regular health checkups, including a health examination survey and blood cadmium measurements. We followed them for 3 years. To investigate the effect of dispatch frequency on blood cadmium levels and the effect of blood cadmium levels on hypertension, we estimated the short-term (model 1) and long-term (model 2) effects of exposure and hypothesized a reversed causal pathway model (model 3) for sensitivity analysis. Sequential conditional mean models were fitted using generalized estimating equations, and the odds ratios (ORs) and the respective 95% confidence intervals (CIs) were calculated for hypertension for log-transformed (base 2) blood cadmium levels and quartiles.

Results

Using the lowest category of dispatch frequency as a reference, we observed that the highest category showed an increase in blood cadmium levels of 1.879 (95% CI: 0.673, 3.086) μg/dL and 0.708 (95% CI: 0.023, 1.394) μg/dL in models 2 and 3, respectively. In addition, we observed that doubling the blood cadmium level significantly increased the odds of hypertension in model 1 (OR: 1.772; 95% CI: 1.046, 3.003) and model 3 (OR: 4.288; 95% CI: 1.110, 16.554). Using the lowest quartile of blood cadmium levels as a reference, the highest quartile showed increased odds of hypertension in model 1 (OR: 2.968; 95% CI: 1.121, 7.861) and model 3 (OR: 33.468; 95% CI: 1.881, 595.500).

Conclusions

We found that dispatch frequency may affect blood cadmium levels in male firefighters, and high blood cadmium levels may influence hypertension in a dose-response manner.

A review on MXene and its nanocomposites for the detection of toxic inorganic gases

In the search of the viable candidate for the sensing of pollutant gases, two-dimensional (2D) material transition metal carbides (MXenes) have attracted immense attention due to their outstanding physical and chemical properties for sensing purposes. The formation of unique 2D layered structure with high conductivity, large mechanical strength, and high adsorption properties furnish their strong interactions with gaseous molecules, which holds a promising place for developing ideal gas sensing devices. This review looks at recent achievements in diversified MXenes, with a focus gaining on in-depth understanding of MXene-based materials in room temperature inorganic gas sensors through both theoretical and experimental studies. In the first part of the review, the properties and advantages of sensing material (MXene) in comparison with other 2D materials are discussed. In the second part, the unique advantages of chemiresistive based sensors and the demerits of other detection methods are summarized in detail. This section is followed by the unique structural design of MXene bases materials for improving the sensing performance towards detection of inorganic gases. The interaction between MXene and the adsorbed gases on its surface is discussed, with a possible sensing mechanism. Finally, an overview of the current progress and opportunities for the demand of MXene is emphasized and perspectives for future improvement of the design of MXene in gas sensors are highlighted. Therefore, this review highlights the opportunities and the advancement in 2D material-based gas sensors which could provide a new avenue for rapid detection of toxic gases in the environment.

Characterising the ground level concentrations of harmful organic and inorganic substances released during major industrial fires, and implications for human health

We report on the concentration ranges and combustion source-related emission profiles of organic and inorganic species released during 34 major industrial fires in the UK. These episodic events tend to be acute in nature and demand a rapid public health risk assessment to indicate the likely impact on exposed populations. The objective of this paper is to improve our understanding of the nature, composition and potential health impacts of emissions from major incident fires and so support the risk assessment process. Real world monitoring data was obtained from portable Fourier Transform Infrared (FTIR) monitoring (Gasmet DX-4030/40) carried out as part of the UK's Air Quality in Major Incidents service. The measured substances include carbon monoxide, sulphur dioxide, nitrogen dioxide, ammonia, hydrogen chloride, hydrogen bromide, hydrogen fluoride, hydrogen cyanide, formaldehyde, 1,3-butadiene, benzene, toluene, xylenes, ethyl benzene, acrolein, phosgene, arsine, phosphine and methyl isocyanate. We evaluate the reported concentrations against Acute Exposure Guideline Values (AEGLs) and Emergency Response Planning Guidelines (ERPGs), as well as against UK, EU and WHO short-term ambient guideline values. Most exceedances of AEGL or ERPG guideline values were at levels likely only to cause discomfort to exposed populations (hydrogen cyanide, hydrogen chloride, hydrogen fluoride and formaldehyde), though for several substances the exceedances could have potentially given rise to more serious health effects (acrolein, phosphine, phosgene and methyl isocyanate). In the latter cases, the observed high concentrations are likely to be due to cross-interference from other substances that absorb in the mid-range of the infrared spectrum, particularly when the ground level plume is very concentrated.

Analysis of 10 Urinary BTEX Metabolites by Liquid Chromatography Tandem Mass Spectrometry

Benzene, toluene, ethylbenzene and xylene (BTEX) are a group of volatile organic compounds that are ubiquitous in the environment due to the numerous anthropogenic sources. Exposure to BTEX pose a health risk by increasing probability for damage to multiple organs, neurocognitive impairment and birth defects. Urinary BTEX metabolites are useful biomarkers for evaluation of BTEX exposure, because of easiness of sampling and their longer physiological half-lives compared with parent compounds. A method that utilizes liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-MS/MS) was developed and validated for simultaneously monitoring ten urinary BTEX metabolites. During the sample preparation an aliquot of urine was diluted by the equal volume of 1% formic acid, internal standards solution was added, then the sample was centrifuged and analyzed. The analytes were separated on the Kinetex-F5 column by applying a linear gradient, consisting of 0.1 % formic acid and methanol. The method was validated according to the FDA Bioanalytical Method Validation Guidance for Industry. The mean method's accuracies of the spiked matrix were 81-122%; the interday precision ranged from 4% to 20%; limits of quantitation were 0.5-2 μg/L. The method was used for evaluation of baseline levels of urinary BTEX metabolites in 87 firefighters.

Evaluation of an Ozone Chamber as a Routine Method to Decontaminate Firefighters' PPE

Ozone chambers have emerged as an alternative method to decontaminate firefighters' Personal Protective Equipment (PPE) from toxic fire residues. This work evaluated the efficiency of using an ozone chamber to clean firefighters' PPE. This was achieved by studying the degradation of pyrene and 9-methylanthracene polycyclic aromatic hydrocarbons (PAHs). The following experiments were performed: (i) insufflating ozone into PAH solutions (homogeneous setup), and (ii) exposing pieces of PPE impregnated with the PAHs to an ozone atmosphere for up to one hour (heterogeneous setup). The ozonolysis products were assessed by Fourier Transform Infrared Spectroscopy (FTIR), Thin-Layer Chromatography (TLC), and Mass Spectrometry (MS) analysis. In the homogeneous experiments, compounds of a higher molecular weight were produced due to the incorporation of oxygen into the PAH structures. Some of these new compounds included 4-oxapyren-5-one (m/z 220) and phenanthrene-4,5-dicarboxaldehyde (m/z 234) from pyrene; or 9-anthracenecarboxaldehyde (m/z 207) and hydroxy-9,10-anthracenedione (m/z 225) from 9-methylanthracene. In the heterogeneous experiments, a lower oxidation was revealed, since no byproducts were detected using FTIR and TLC, but only using MS. However, in both experiments, significant amounts of the original PAHs were still present even after one hour of ozone treatment. Thus, although some partial chemical degradation was observed, the remaining PAH and the new oxygenated-PAH compounds (equally or more toxic than the initial molecules) alerted us of the risks to firefighters' health when using an ozone chamber as a unique decontamination method. These results do not prove the ozone-advertised efficiency of the ozone chambers for decontaminating (degrading the toxic combustion residues into innocuous compounds) firefighters' PPE.