Toward the future of firefighter gear: Assessing fluorinated and non-fluorinated outer shells following simulated on-the-job exposures

In 2022, the occupation of firefighting was categorized as a "Group 1" carcinogen, meaning it is known to be carcinogenic to humans. The personal protective equipment that structural firefighters wear is designed to safeguard them from thermal, physical, and chemical hazards while maintaining thermo-physiological comfort. Typically, the outer layer of structural turnout gear is finished with a durable water and oil-repellent (DWR) based on per- and polyfluoroalkyl substances (PFAS) that helps limit exposure to water and hazardous liquids. The PFAS-based aqueous emulsion typically used in DWR finishes is highly persistent and can cause various health problems if absorbed into the body through ingestion, inhalation, and/or dermal absorption. In response, the U.S. Fire Service has begun using non-PFAS water repellants in firefighter turnout gear. This study aims to evaluate the performance of both traditional PFAS-based and alternative non-PFAS outer shell materials. The study involved exposing both PFAS-based and non-PFAS DWR outer shell materials in turnout composites to simulated job exposures (i.e., weathering, thermal exposure, and laundering) that artificially aged the materials. After exposures, samples were evaluated for repellency, durability, thermal protection, and surface chemistry analysis to determine any potential performance trade-offs that may exist. Non-PFAS outer shell fabrics were found not to be diesel/oil-repellent, posing a potential flammability hazard if exposed to diesel and subsequent flame on an emergency response. Both PFAS-based and non-PFAS sets of fabrics performed similarly in terms of thermal protective performance, tearing strength, and water repellency. The surface analysis suggests that both PFAS and non-PFAS chemistries can degrade and shed from fabrics during the aging process. The study indicates that firefighters should be educated and trained regarding the potential performance trade-offs, such as oil absorption and flammability concerns when transitioning to non-PFAS outer shell materials.

Survival of Staphylococcus aureus on the outer shell of fire fighter turnout gear after sanitation in a commercial washer/extractor

Background

Methicillin-resistant Staphylococcus aureus contamination on surfaces including turnout gear had been found throughout a number of fire stations. As such, the outer shell barrier of turnout gear jackets may be an indirect transmission source and proper disinfection is essential to reduce the risk of exposure to fire fighters. Cleaning practices vary considerably among fire stations, and a method to assess disinfection of gear washed in commercial washer/extractors is needed.

Methods

Swatches (1 in. ×  1.5 in.) of the outer shell fabrics, Gemini™, Advance™, and Pioneer™, of turnout gear were inoculated with S. aureus, and washed with an Environmental Protection Agency-registered sanitizer commonly used to wash turnout gear. To initially assess the sanitizer, inoculated swatches were washed in small tubes according to the American Society for Testing Materials E2274 Protocol for evaluating laundry sanitizers. Inoculated swatches were also pinned to turnout gear jackets and washed in a Milnor commercial washer/extractor. Viable S. aureus that remained attached to fabric swatches after washing were recovered and quantified. Scanning Electron Microscopy was used to characterize the stages of S. aureus biofilm formation on the swatches that can result in resistance to disinfection.

Results

Disinfection in small tubes for only 10 s reduced the viability of S. aureus on Gemini™, Advance™, and Pioneer™ by 73, 99, and 100%, respectively. In contrast, disinfection of S. aureus-contaminated Gemini™ swatches pinned to turnout gear and washed in the washer/extractor was 99.7% effective. Scanning Electron Microscopy showed that biofilm formation begins as early as 5 h after attachment of S. aureus.

Conclusion

This sanitizer and, likely, others containing the anti-microbial agent didecyl dimethyl ammonium chloride, is an effective disinfectant of S. aureus. Inclusion of contaminated outer shell swatches in the wash cycle affords a simple and quantitative method to assess sanitization of gear by commercial gear cleaning facilities. This methodology can be extended to assess for other bacterial contaminants. Sanitizer-resistant strains will continue to pose problems, and biofilm formation may affect the cleanliness of the washed turnout gear. Our methodology for assessing effectiveness of disinfection may help reduce the occupational exposure to fire fighters from bacterial contaminants.

Occupational safety and health protections against Ebola virus disease

Even as the Ebola epidemic is finally showing signs of remitting, controversy continues regarding the modes of disease transmission, the understanding of which necessarily dictates methods of prevention. The initial public health response to the epidemic was based on assumptions formed during previous outbreaks, and in the belief that transmission was restricted to direct "contact" with other infected patients. However, the current Ebola outbreak differed from previous experiences in its intensity of transmission, speed of spread, and fatality rate and was also particularly unforgiving on health workers occupationally infected. Even with these differences, however, other modes of transmission were not considered by public health authorities, thus denying both the hard-hit health worker populations and the wider public more protective guidance. International Labor Conventions require employers to provide a comprehensive safety program that anticipates work-related risks and specifies strategies for protection against them. Such a precautionary approach is recommended in future epidemic planning, especially where evidence regarding transmission is incomplete.

A Suggested Approach to the Selection of Chemical and Biological Protective Clothing—Meeting Industry and Emergency Response Needs for Protection Against a Variety of Hazards

The paper describes the development of a comprehensive decision logic for selection and use of biological and chemical protective clothing (BCPC). The decision logic recognizes the separate areas of BCPC use among emergency, biological, and chemical hazards. The proposed decision logic provides a system for type classifying BCPC in terms of its compliance with existing standards (for emergency applications), the overall clothing integrity, and the material barrier performance. Type classification is offered for garments, gloves, footwear, and eye/face protection devices. On the basis of multiple, but simply designed flowcharts, the type of BCPC appropriate for specific biological and chemical hazards can be selected. The decision logic also provides supplemental considerations for choosing appropriate BCPC features.

A comparative analysis of glove permeation resistance to paint stripping formulations

Although there is a wide variety of work gloves available to users of commercial paint stripping products, there are no published studies examining which type of gloves provide the best protection. To address this need, a multiphase study was undertaken to evaluate how several types of gloves resist multichemical-based paint stripping formulations. Due to the wide range of commercial paint stripping formulations available, seven categories of surrogate paint stripper formulations were created to evaluate glove performance initially. Twenty different glove types were identified for initial evaluation. Degradation resistance screening was carried out for each glove style and paint stripping formulation. Screening results were used to identify those glove styles least affected by the surrogate paint strippers. Those gloves were then evaluated for their resistance to permeation using continuous contact testing based on ASTM Test Method F 739. Glove styles showing extensive permeation with early breakthrough were then evaluated to see how they performed with only intermittent contact with the surrogate paint strippers using a modified form of ASTM Test Method F 1383. These results were used to select glove styles to be tested using commercially available paint stripping products. Gloves made of plastic laminate and butyl rubber were the most effective against the majority of paint strippers. More glove styles resisted permeation by N-methylpyrrolidone and dibasic ester-based paint strippers than conventional solvent products such as methylene chloride, methanol, isopropanol, acetone, and toluene. The study also found that decreased contact time caused relatively little change in permeation resistance and that the surrogate paint stripper data did not always accurately predict resistance to the commercial paint stripper formulations.

The impact of protective hoods and their water content on the prevention of head burns in New York City firefighters: laboratory tests and field results

The New York City Fire Department (FDNY) is the largest fire department in the United States. In 1996, FDNY added the thermal protective hood to its modern protective uniform. The purpose of this study is to determine 1) the effectiveness of hoods in reducing head burns and 2) whether hood water content (dry, damp, or saturated) affects the level of thermal protection. Laboratory tests (radiant heat performance, thermal protective performance, and fully dressed manikin) and FDNY field results were used. Laboratory tests evaluated 4 different conditions (no hood, dry, damp, and saturated hoods) exposed to 4 different heat fluxes (0.1, 0.25, 0.5, and 2.0 cal/cm2/sec) equivalent to approximate air temperatures of 200, 400, 600, and 2,250 degrees F. Field results compared FDNY head burns during 3 winters wearing the hood to 3 winters without hood. Wearing a hood dramatically reduced head burns. This was true for all laboratory tests, at all heat flux exposures, and all hood water content conditions. At 0.1 cal/cm2/sec, dry hoods were superior to wet hoods. At all other heat flux exposures, thermal protection was either not significantly different between water content conditions or improved as water content increased. Confirming these laboratory tests, FDNY field results showed significant decreases in neck burns (by 54%), ear burns (by 60%), and head burn totals (by 46%). Based on combined laboratory and field results, we strongly recommend the use of modern thermal protective hoods.

Selection and testing of a glove combination for use with the U.S. Coast Guard's chemical response suit

A study was sponsored by the U.S. Coast Guard to select a glove system for its chemical response suit that could meet or exceed the chemical resistance performance of the suit's base material. Three different protective glove combinations were evaluated for their permeation resistance to 28 chemicals. The glove combinations were based on three materials--Viton, butyl rubber, and Silvershield. The test chemicals were selected for one of two reasons. First, no single glove material could be identified to be resistant against the chemical of interest, or second, no permeation test data were available for judging glove material performance for the specific chemical. As can be expected, the permeation resistance of the glove combinations greatly exceeded that of the single glove material components. The butyl rubber/Silvershield glove combination was found to provide permeation resistance greater than 1 hr for all but one of the chemicals tested.

Special considerations for conducting permeation testing of protective clothing materials with gases and chemical vapors

Testing the permeation resistance of protective clothing materials against chemical gases and vapors requires attention to additional factors over conventional material permeation testing with liquids. Permeation testing factors relevant to gas and vapor challenges are described, and results for testing various material-gas combinations are reported. Challenging protective clothing materials with gases presents a series of special problems including gas delivery, cell integrity, sufficient analytical detection, and disposal. The concentration and other properties of gases and vapors are very sensitive to small changes in temperature and pressure. The method of delivering gases or vapors to the test cell must provide for careful regulation of these variables and maintain homogeneous contact of the chemical with the material over the test period. While many organic vapors are easily and directly detectable by gas chromatographic methods, several gases require special collection media and analytical procedures to achieve detection limits below 1 ppm. Handling of exhaust gas from the challenge chamber of the test cell must reflect safe laboratory practices without creating unnecessary chemical waste. Recommended procedures and results are presented for the six new gases added to ASTM Standard Guide F1001, Selection of Chemical Liquids and Gases to Evaluate Protective Clothing Materials, as well as for other difficult test gases used in evaluating protective clothing materials.