Toxic Chemical Transfer Through PPE

What if the personal protective equipment designed to protect the fire service is actually allowing toxic chemicals produced in fires to reach their skin? The Toxic Chemicals Transfer Through PPE (InToxFIRE) project investigates gaps in firefighter turnout gear protection, which may help explain elevated firefighter cancer risks.

Led by the Fire Safety Engineering Research and Technology Centre (FireSERT) at Ulster University, with support from the Fire Safety Research Institute, part of UL Research Institutes, this research explores how toxic chemicals can penetrate firefighters' protective gear through the fabric’s breathable membranes. Through this project, researchers aim to increase the understanding of current PPE protection and recommend changes to advance firefighter health and safety. Ulster University is a recipient of the ULRI Discoveries in Safety Grants program, a three-year award given to outstanding researchers dedicated to furthering safety research.

A Three-Phase Approach to Testing PPE and Understanding Firefighter Cancer Risks

This research primarily focuses on the breathable membrane in the middle layer of firefighter PPE. These membranes are designed to allow sweat to escape from the firefighter's body, keeping them cooler during intense heat. However, when a firefighter’s body is cooler than their surrounding environment, this process may be reversed. This understudied pathway of toxic chemical ingress may be one reason why firefighters' cancer rates are elevated compared to the national average.

To better explore these mechanisms, researchers will carry out this project in three phases.

Phase 1: Small-Scale Laboratory Testing

Ulster University’s researchers begin with a review of existing research on small-scale testing protocols. After confirming the test setup in collaboration with FSRI researchers, they conduct exposure tests using ~4-inch-wide swatches of firefighter jackets. The swatches are sourced from clean and dirty firefighter turnout gear from both the UK, EU, and the US, with FSRI researchers providing commonly used US protective equipment for testing, including NFPA 1970-compliant gear. During the controlled tests, researchers collect and analyze toxic mixtures to identify which chemicals penetrate protective layers and in what concentrations. This analysis results in a list of the most concerning toxins to test in the next phase of the study.

Phase 2: Medium-Scale Testing

Building on the laboratory findings, this phase scales up Phase 1 research to test larger PPE swatches in a controlled testing environment. Researchers use specialized equipment, including tube furnaces or fire propagation apparatuses, to examine how heat and toxins transfer through complete clothing ensembles under controlled fires that more closely simulate real firefighting conditions. This testing focuses on the priority toxins identified in Phase 1, allowing researchers to observe chemical movement through full protective gear systems rather than individual fabric samples.

Phase 3: Computer Modeling and Analysis

The final testing phase uses two forms of numerical modeling to predict and quantify toxic heat and mass transfer through fire protective gear. The simple heat transfer model analyzes the transfer of heat through the layers of protective gear under various environmental conditions. The advanced 3D finite element analysis model analyzes the design of PPE in detail to examine how factors like environmental temperature, humidity, fabric type, and porosity affect chemical penetration. The analyses from these models allow researchers to predict toxin exposure levels under different firefighting conditions and evaluate potential design improvements.

Novel Research Approach Targets Practical Solutions for Firefighter Cancer Risk

The aftermath of high-profile incidents, such as the Grenfell Tower fire, where first responders have been diagnosed with terminal cancers, underscores the urgency of this research. While most studies have examined entire PPE ensembles or how exposures can occur through openings between PPE components, this is among the first to specifically investigate how toxins move through protective gear layers, providing crucial insights into the underlying mechanisms of the exposure. In addition, Ulster University experiments with both clean and contaminated PPE, as well as various durable water repellent treatments (fluorinated and non-fluorinated), which will provide a better understanding of chemical transfer, the effectiveness of decontamination protocols, and the risks associated with contaminated gear.

This project aims to develop comprehensive improvements to firefighter health and safety, including improved firefighter personal protective equipment, decontamination protocols, donning and doffing procedures, and firefighting training. This research will also issue recommendations on firefighter gear design and PPE testing regulations.