Contamination and laundering of firefighter undergarments following wildland fire exposure

Background Undergarments worn beneath protective clothing during bushfire operations may retain smoke-related contaminants, potentially exposing firefighters even after firefighting activities have ended. Aims We investigated contamination of firefighter undergarments, the effectiveness of laundering and the potential for contamination to transfer between wash loads. Methods Cotton undergarments worn during bushfire and prescribed burn operations in Western Australia were analysed using Fourier transform infrared spectroscopy, with formaldehyde as the primary marker of contamination. We assessed warm (40°C, n = 15) and cold (~20°C, n = 7) washing, repeat laundering and contamination transfer to clean garments washed after contaminated loads, with or without an intervening empty hot wash cycle. Key results Exposed undergarments released measurable formaldehyde. Warm washing reduced mean formaldehyde concentrations from 0.12 to 0.01 parts per million (ppm), a reduction of 91%, whereas cold washing reduced concentrations from 0.21 to 0.06 ppm (71%). Rewashing the cold-washed garments at 40°C produced no statistically significant further reduction. Clean garments washed after contaminated loads showed increased contamination, whereas an intervening empty hot wash reduced concentrations to near-baseline levels. Conclusions Laundering substantially reduced formaldehyde off-gassing, but contamination could transfer between loads. Implications Empty hot wash cycles may help limit cross-contamination when laundering firefighter clothing.