Improvement to the integrity of laser powder bed fusion (PBF-LB) processed Nickel-base superalloys is crucial for their wider adoption in industrial aerospace applications. The nature of PBF-LB, essentially an extended powder micro-welding process, allows opportunity for material contamination and oxidisation. This study reports how oxide formation occurs in Hastelloy X corresponding to ASTM composition, and in particular, in the material ejected from the process zone during fabrication (spatter). It is shown that oxidation occurs despite processing in an Ar atmosphere with <0.2% O-2, and moreover, this can result in oxide inclusions in built parts. The spatter particles are also associated with part defects. Depending on the sieve size used, 30-60% of oxidised spatter particles are within the size range to be recycled and reprocessed in subsequent uses. This impacts the processing of powder in PBF-LB, powder quality in use in the technology, and powder manufacture in the industry. (C) 2019 Elsevier B.V. All rights reserved.