An expert peer consultation panel reviewed a report by the PAC Analysis Task Group, which hypothesized that systemic, developmental, and reproductive toxicity observed in repeated-dose dermal toxicity studies was related to polycyclic aromatic compound (PAC) content. Peer consultations seek to solicit scientific and technical input from experts on the scientific basis and merits of the subject report. This peer consultation panel included nine scientists with expertise in petroleum chemistry, biostatistics, toxicology, risk assessment, structure activity, and reproductive and developmental toxicology. The panel evaluated the technical quality of the PAC report and provided recommendations for improving the statistical and biological approaches. The PAC report authors revised their methods and documentation, which are published elsewhere in this supplement. A review of the post peer consultation manuscripts confirmed that many of the key suggestions from expert panel members were considered and incorporated. In cases where the PAC report authors did not fully incorporate panel suggestions from the peer consultation, they have provided an explanation and support for their decision. This peer consultation demonstrates the value of formal engagement of peers in development of new scientific methods and approaches.