Welding activities expose millions of workers to metal-containing nanoparticles (NPs) present in fumes. While inhalation is well-recognized as a major health risk, the potential for skin exposure, especially under inconsistent use of protective equipment, has been largely overlooked. The impact of different welding configurations on NP toxicity remains poorly understood as well. This study employs an ex vivo human skin model to investigate the dermal penetration of NPs from two common welding fume sources: solid wire and flux-cored wire. Gold (Au) and nickel oxide (NiO) nanoparticles (NPs) are employed as benchmarks for the assessment of dermal penetration. Formalin-fixed paraffin-embedded (FFPE) skin sections were prepared and labeled with a panel of up to 30 metal-tagged antibodies and analyzed via laser ablation-inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOFMS) imaging. This approach provides high-resolution elemental mapping, enabling the comprehensive assessment of tissue architecture, cell types and quantitative analysis of metal uptake. Our findings offer a detailed assessment of the composition and distribution of multi-element NPs from welding fumes and their interactions with human skin. These insights are critical for understanding potential dermal toxicity and guiding improved protective measures in occupational settings.