Reducing respirable silica exposure among brick kiln workers in Nepal: a human-centred design and implementation science framework to develop and pilot a personal protective equipment intervention.

Abstract

Brick kiln workers in Nepal face high exposure to respirable silica but are not required to use personal protective equipment (PPE). We sought to understand factors influencing PPE use, design and pilot a PPE training and distribution intervention and assess its feasibility. We used a human-centred design approach guided by the Discover, Design, Build, Test framework and conducted four pre-intervention workshops (36 participants), a 21-day randomised controlled trial (RCT) and three post-intervention workshops (19 participants) at a kiln in Bhaktapur, Nepal. Workers and leadership aged ≥18 years were purposively sampled for workshops and randomly selected for the RCT (20 intervention, 20 control). Intervention participants received PPE training, weekly reminders and free N95 respirators and eyewear. Control participants received counselling and information on where to purchase PPE. Pre-intervention workshops revealed barriers to PPE use, including cost, discomfort and work efficiency concerns. Workers preferred expert-led, hands-on PPE training. We identified high feasibility (mean Feasibility of Intervention Measure, 4.6±0.5 points) among workers; leadership rated feasibility lower due to cost concerns. Observed N95 use was higher in the intervention group (78.9%, 71/90 visits) compared with none in the control group (0%, 0/93 visits; p<0.001). Post-intervention feedback showed workers felt N95s reduced dust exposure and respiratory symptoms without impacting efficiency, but eyewear needed adaptation for sustained use. With worker-centred training, N95 respirators are feasible to reduce silica exposure in this setting. However, broader adoption may depend on improving the affordability and accessibility of PPE through advocacy and policy changes. NCT06090370.