Laser Powder Bed Fusion (L-PBF) is an additive manufacturing process, which allows to produce metallic parts layer by layer. The reuse of the powder is critical for cost part. The reuse can modify the powder and thus the printed parts properties. This study is focused on a severe reuse of 6061-Zr by analyzing the physico-chemical features of the powder, their impact on both the printed parts and toxicological properties. The results of this study showed a high physico-chemical stability of 6061-Zr powder under severe reuse even if oxygen content increase on the reused powder. This study highlights the high amount of oxygen and the variation in chemical composition of the sieving residue. Besides, the toxicological properties of the powder and the mechanical features of the printed parts are unchanged. These results show that in addition to guaranteeing a specific particle size, sieving limits the oxygen increase and the chemical modification of the powder.