“…To optimize parameters used in estimation models, WHO and ILO are conducting a systematic review and meta-analysis of studies that include estimates of the effect of occupational exposure to welding fumes on trachea, bronchus and lung cancer. In this article, we present the protocol for this systematic review, in parallel to presenting systematic review protocols or completed systematic reviews on other additional risk factor-outcome pairs elsewhere ( Descatha et al, 2018 , Descatha et al, 2020 , Godderis et al, 2018 , Hulshof et al, 2019 , Li et al, 2018 , Li et al, 2020 , Mandrioli et al, 2018 , Paulo et al, 2019 , Rugulies et al, 2019 , Teixeira et al, 2019 , Tenkate et al, 2019 ). The WHO/ILO joint estimation methodology and the WHO/ILO Joint Estimates are separate from these systematic reviews; they will be described and reported elsewhere.…”