The findings reflect and expand on those made for other types of combustion-derived material (e.g., PAHs). Extracts of ash collected from forest fires at the wildland-urban interface were assessed for their AhR, ER, AR, interleukin-8, and cyclooxygenase-2 (COX-2) activity, which largely reflected the bioactivity of common combustion-derived chemicals of concern. There were some indications that other compounds contributed to the total bioactivity. However, their extent of activation was no more than that of the more common chemicals from an AhR activation standpoint. The FACTORIAL profiling of the pyroplastics for a much larger number of end points suggests a similar conclusionthe bioactivity reflected that of common combustion-derived chemicals of concern (i.e., PAHs). Nonetheless, while the FACTORIAL platform provides a valuable screen for bioactivity, an ensemble of measures (e.g., transcriptomics and other methods) is necessary to fully understand the potential modes of toxicity for a contaminant. Moreover, the pyroplastics from the X-Press Pearl disaster were formed following the combustion of polyethylene. Other compounds of concern (e.g., dioxins, PFAS) can be formed during the combustion of halogenated and heteroatom-containing polymers. Thus, investigating pyroplastics from diverse plastics is necessary to more broadly confirm this similarity to other types of combustion-derived material.