Ultraviolet resistance additives are critical for plastic parts that are exposed to harsh environmental conditions. Typical additive packages are designed to last a given amount of time, due to the fact that the active chemical species are consumed overtime. A parallel approach consists on blocking incoming light by means of a filler or opacifier. As side benefits, permeability can be enhanced due to blocking of the diffusing molecules. Additionally, mechanical properties can be improved via the addition of such mineral fillers. Mineral fillers such as iron oxide have been known and available as fillers for plastics and coatings for a long time; however, several side effects that can be traced back to impurities in such fillers have opposed their potential use. The availability of higher purity iron oxide can be used advantageously as a ultraviolet-blocking agent that can be used as a partial or total replacement of standard chemical ultraviolet-resistance additive packages.