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.

Smoke toxicity of rainscreen façades.

The toxic smoke production of four rainscreen façade systems were compared during large-scale fire performance testing on a reduced height BS 8414 test wall. Systems comprising 'non-combustible' aluminium composite material (ACM) with polyisocyanurate (PIR), phenolic foam (PF) and stone wool (SW) insulation, and polyethylene-filled ACM with PIR insulation were tested. Smoke toxicity was measured by sampling gases at two points - the exhaust duct of the main test room and an additional 'kitchen vent', which connects the rainscreen cavity to an occupied area. Although the toxicity of the smoke was similar for the three insulation products with non-combustible ACM, the toxicity of the smoke flowing from the burning cavity through the kitchen vent was greater by factors of 40 and 17 for PIR and PF insulation respectively, when compared to SW. Occupants sheltering in a room connected to the vent are predicted to collapse, and then inhale a lethal concentration of asphyxiant gases. This is the first report quantifying fire conditions within the cavity and assessing smoke toxicity within a rainscreen façade cavity.

Burning behaviour of rainscreen façades.

Four reduced-height (5 m) BS 8414-1 façade flammability tests were conducted, three having mineral-filled aluminium composite material (ACM-A2) with polyisocyanurate (PIR) and phenolic (PF) foam and stone wool (SW) insulation, the fourth having polyethylene-filled ACM (ACM-PE) with PIR insulation. Each façade was constructed from a commercial façade engineer's design, and built by practising façade installers. The ACM-PE/PIR façade burnt so ferociously it was extinguished after 13.5 min, for safety. The three ACM-A2 cladding panels lost their structural integrity, and melted away from the test wall, whereupon around 40% of both the combustible PIR and PF insulation burnt and contributed to the fire spread. This demonstrates why all façade products must be non-combustible, not just the outer panels. For the three ACM-A2 tests, while the temperature in front of the cavity was independent of the insulation, the temperatures within it varied greatly, depending on the insulation. The system using PF/A2 allowed fire to break through to the cavity first, as seen by a sharp increase in temperature after 17 min. For PIR/A2, the temperature increased sharply at 22 minutes, as the panel started to fall away from the wall. For SW/A2, no rapid temperature rise was observed.

Environmental contamination following the Grenfell Tower fire.

The Grenfell Tower fire in central London, started within a flat, engulfed the whole 24 storey building in flames, killed 72 people and spread toxic effluent via the plume and particulate deposits. Soil samples from 6 locations up to 1,2 km from the Tower, together with semi-burnt fire debris and char samples, were collected 1 and 6 months after the fire. Additionally, dust samples and condensates were collected from a flat 160 m away from the Tower after 17 months. Samples were analysed for common potentially toxic components of fire effluents and synthetic vitreous fibres. Samples collected within 140 m of the Tower showed, amongst other toxicants, polychlorinated dibenzo-p-dioxin concentrations 60 times greater than UK urban reference soil levels; benzene levels were 40 times greater; levels of 6 key polycyclic aromatic hydrocarbons (PAHs) were approximately 160 times greater. PAHs levels are approximately 20 times greater than those reported from nearby Hyde Park before the fire. To explain the presence of these pyrogenic contaminants char and partially burnt debris were also collected and analysed. Benzene, PAHs, isocyanates and phosphorus flame retardants were found. Hydrogen cyanide and synthetic vitreous fibres were present in both soil and debris. Particulate and pyrogenic contamination in the immediate vicinity is clearly evident, and may have leached out of fire debris, char and dust. Further analysis of the area around the Tower is necessary to understand potential health risks.

Fire behaviour of modern façade materials - Understanding the Grenfell Tower fire.

The 2017 Grenfell Tower fire spread rapidly around the combustible façade system on the outside of the building, killing 72 people. We used a range of micro- and bench-scale methods to understand the fire behaviour of different types of façade product, including those used on the Tower, in order to explain the speed, ferocity and lethality of the fire. Compared to the least flammable panels, polyethylene-aluminium composites showed 55x greater peak heat release rates (pHRR) and 70x greater total heat release (THR), while widely-used high-pressure laminate panels showed 25x greater pHRR and 115x greater THR. Compared to the least combustible insulation products, polyisocyanurate foam showed 16x greater pHRR and 35x greater THR, while phenolic foam showed 9x greater pHRR and 48x greater THR. A few burning drips of polyethylene from the panelling are enough to ignite the foam insulation, providing a novel explanation for rapid flame-spread within the facade. Smoke from polyisocyanurates was 15x, and phenolics 5x more toxic than from mineral wool insulation. 1 kg of burning polyisocyanurate insulation is sufficient to fill a 50m3 room with an incapacitating and ultimately lethal effluent. Simple, additive models are proposed, which provide the same rank order as BS8414 large-scale regulatory tests.

Stability of Isocyanates Sampled in Fire Smokes.

Inhalation of airborne isocyanates is associated with acute asthma attacks and inflammation in the respiratory tract as well as cancer. These highly reactive compounds are used as monomers in various applications such as foams for insulation materials and upholstery furniture and are therefore commonly found in fire smoke from insulation materials, such as rigid polyisocyanurate (PIR) foams. Consequently, there is an increasing concern regarding the potential adverse health effects they may cause during this type of exposure.The aim of this study was to investigate the stability of generated isocyanates from aerobic pyrolysis of PIR after sampling in the derivatization solution as well as after sample preparation to establish the optimal storage conditions and rate of degradation. Both airborne and particle-bound isocyanates were collected, using dibutylamine as derivatization agent in a midget impinger and impregnated filter after the impinger. The rapid degradation of the generated isocyanates after sampling emphasizes the need for a prompt sample preparation and analysis, in particular for the collected mono-isocyanates, as the concentration decreased by 50% within 4-8 h.

Occupational Exposure to Polycyclic Aromatic Hydrocarbons and Elevated Cancer Incidence in Firefighters.

Cancer incidence appears to be higher amongst firefighters compared to the general population. Given that many cancers have an environmental component, their occupational exposure to products of carbon combustion such as polycyclic aromatic hydrocarbons (PAHs) is of concern. This is the first UK study identifying firefighters exposure to PAH carcinogens. Wipe samples were collected from skin (jaw, neck, hands), personal protective equipment of firefighters, and work environment (offices, fire stations and engines) in two UK Fire and Rescue Service Stations. Levels of 16 US Environmental Protection Agency (EPA) PAHs were quantified together with more potent carcinogens: 7,12-dimethylbenzo[a]anthracene, and 3-methylcholanthrene (3-MCA) (12 months post-initial testing). Cancer slope factors, used to estimate cancer risk, indicate a markedly elevated risk. PAH carcinogens including benzo[a]pyrene (B[a]P), 3-MCA, and 7,12-dimethylbenz[a]anthracene PAHs were determined on body surfaces (e.g., hands, throat), on PPE including helmets and clothing, and on work surfaces. The main exposure route would appear to be via skin absorption. These results suggest an urgent need to monitor exposures to firefighters in their occupational setting and conduct long-term follow-up regarding their health status.

Flame retardants in UK furniture increase smoke toxicity more than they reduce fire growth rate.

This paper uses fire statistics to show the importance of fire toxicity on fire deaths and injuries, and the importance of upholstered furniture and bedding on fatalities from unwanted fires. The aim was to compare the fire hazards (fire growth and smoke toxicity) using different upholstery materials. Four compositions of sofa-bed were compared: three meeting UK Furniture Flammability Regulations (FFR), and one using materials without flame retardants intended for the mainland European market. Two of the UK sofa-beds relied on chemical flame retardants to meet the FFR, the third used natural materials and a technical weave in order to pass the test. Each composition was tested in the bench-scale cone calorimeter (ISO 5660) and burnt as a whole sofa-bed in a sofa configuration in a 3.4 × 2.25 × 2.4 m3 test room. All of the sofas were ignited with a No. 7 wood crib; the temperatures and yields of toxic products are reported. The sofa-beds containing flame retardants burnt somewhat more slowly than the non-flame retarded EU sofa-bed, but in doing so produced significantly greater quantities of the main fire toxicants, carbon monoxide and hydrogen cyanide. Assessment of the effluents' potential to incapacitate and kill is provided showing the two UK flame retardant sofa-beds to be the most dangerous, followed by the sofa-bed made with European materials. The UK sofa-bed made only from natural materials (Cottonsafe®) burnt very slowly and produced very low concentrations of toxic gases. Including fire toxicity in the FFR would reduce the chemical flame retardants and improve fire safety.

Analysis of fire deaths in Poland and influence of smoke toxicity.

Dwelling fires have changed over the years because building contents and the materials used in then have changed. They all contribute to an ever-growing diversity of chemical species found in fires, many of them highly toxic. These arise largely from the changing nature of materials in interior finishes and furniture, with an increasing content of synthetic materials containing higher levels of nitrogen, halogen and phosphorus additives. While there is still a belief that carbon monoxide is the major lethal toxic agent in fires, the hydrogen cyanide and acid gases released from these additives are now well-recognised as major contributory causes of incapacitation, morbidity and mortality in domestic fires. Data for the total number of 263 fire death cases in the Mazowieckie region (mainly Warsaw area) of Poland between 2003-2011 for dwellings fires were obtained from pathologists, forensic toxicologists, fire fighters and analysed. Factors contributing to the death such as the findings of the full post mortem examination (age, sex, health status, burns), the toxicological analysis (carbon monoxide, alcohol etc.), and a thorough investigation of the scene (fire conditions, fuel, etc.) were taken into account and are summarised.

Release of volatile and semi-volatile toxicants during house fires.

Qualitative results are presented from analysis of volatile and semi-volatile organic compounds (VOCs/SVOCs) obtained through sampling of gaseous effluent and condensed particulates during a series of experimental house fires conducted in a real house. Particular emphasis is given to the 16 polycyclic aromatic hydrocarbons (PAHs) listed by the Environmental Protection Agency due to their potentially carcinogenic effects. The initial fuel packages were either cooking oil or a single sofa; these were burned both alone, and in furnished surroundings. Experiments were performed at different ventilation conditions. Qualitative Gas Chromatography-Mass Spectrometry (GC-MS) analysis found VOC/SVOC releases in the developing stages of the fires, and benzo(a)pyrene - the most carcinogenic PAH - was found in at least one sampling interval in the majority of fires. A number of phosphorus fire retardants were detected, in both the gaseous effluent and particulates, from fires where the initial fuel source was a sofa. Their release during the fire is significant as they pose toxicological concerns separate from those presented by the PAHs.

A review of exposure and toxicological aspects of carbon nanotubes, and as additives to fire retardants in polymers.

Carbon nanotubes (CNTs) have attracted considerable interest due to their unique physical, chemical, optical and electrical properties opening avenues for a large number of industrial applications. They have shown potential as fire retardant additives in polymers, reducing heat release rate and increasing time to ignition in a number of polymers. Relevant work on the types, properties and applications has been reviewed particularly considering their application in fire situations. There are concerns over the health risks associated with CNTs and many papers have likened CNTs to the health problems associated with asbestos. There are contradictions relating to the toxicity of CNTs with some papers reporting that they are toxic while others state the opposite. Directly comparing various studies is difficult because CNTs come in many combinations of size, type, purity levels and source. CNTs can potentially be released from polymers during the combustion process where human exposure may occur. While this review has shed some light regarding issues relating to toxicity under different fire scenarios much more thorough work is needed to investigate toxicity of CNTs and their evolution from CNT-polymer nanocomposites in order to reach firm conclusions.

Self-assembly fabrication of hollow mesoporous silica@Co-Al layered double hydroxide@graphene and application in toxic effluents elimination.

Here, we propose a self-assembly process to prepare hierarchical HM-SiO2@Co-Al LDH@graphene, with the purpose of combining their outstanding performance. Hollow mesoporous silica was first synthesized as the core, using a novel sonochemical method, followed by a controlled shell coating process and chemical reduction. As a result of the electrostatic potential difference among HM-SiO2, Co-Al LDH, and graphene oxide, the HM-SiO2 spheres were coated by Co-Al LDH and graphene. Subsequently, the HM-SiO2@Co-Al LDH@graphene spheres were introduced into an epoxy resin (EP) matrix for investigation of their toxic effluents capture and elimination effectiveness during combustion. The amount of toxic CO and volatile organic compounds from the epoxy resin decomposition significantly suppressed after incorporating the HM-SiO2@Co-Al LDH@graphene hybrids, implying a reduced toxicity.

Synthesis of mesoporous silica@Co-Al layered double hydroxide spheres: layer-by-layer method and their effects on the flame retardancy of epoxy resins.

Hierarchical mesoporous silica@Co-Al layered double hydroxide (m-SiO2@Co-Al LDH) spheres were prepared through a layer-by-layer assembly process, in order to integrate their excellent physical and chemical functionalities. TEM results depicted that, due to the electrostatic potential difference between m-SiO2 and Co-Al LDH, the synthetic m-SiO2@Co-Al LDH hybrids exhibited that m-SiO2 spheres were packaged by the Co-Al LDH nanosheets. Subsequently, the m-SiO2@Co-Al LDH spheres were incorporated into epoxy resin (EP) to prepare specimens for investigation of their flame-retardant performance. Cone results indicated that m-SiO2@Co-Al LDH incorporated obviously improved fire retardant of EP. A plausible mechanism of fire retardant was hypothesized based on the analyses of thermal conductivity, char residues, and pyrolysis fragments. Labyrinth effect of m-SiO2 and formation of graphitized carbon char catalyzed by Co-Al LDH play pivotal roles in the flame retardance enhancement.

Experimental results of a residential house fire test on tenability: temperature, smoke, and gas analyses.

A fire experiment conducted in a British 1950s-style house is described. Measurements of temperature, smoke, CO, CO2 , and O2 were taken in the Lounge, stairwell, and front and back bedrooms. The front bedroom door was wedged open, while the door to the back bedroom was wedged closed. Contrary to expectations and despite the relatively small fire load, analysis and hazard calculations show permeation of toxic fire gases throughout the property with lethal concentrations of effluent being measured at each sampling point. A generally poor state of repair and missing carpets in the upper story contributed to a high degree of gas and smoke permeation. The available egress time was calculated as the time before the main escape route became impassable. Given known human responses to fire, such an incident could have caused fatalities to sleeping or otherwise immobile occupants.