EPA established a Task Force of senior scientists, knowledgeable in the fields of hazard and exposure assessment, to help it identify the types of information that would be appropriate for evaluating the safety of pesticides for infants and children. The Task Force included representatives from the Agency's Office of Prevention, Pesticides and Toxic Substances; Office of Research and Development; Office of Children's Health Protection; Office of Water; and Office of Solid Waste and Emergency Response. The Task Force made many useful recommendations considered by the Office of Pesticide Programs during the development of this guidance. Comments from the public and from the FIFRA Scientific Advisory Panel also contributed to this document. This document describes how the Office of Pesticide Programs (OPP) determines the appropriate FQPA safety factor(s) when developing aggregate risk assessments and regulatory decisions for single active and 'other' (i.e., inert) ingredients of pesticide products. The guidance is specifically addressed to OPP risk assessors but also serves as an important source of information for the public and the regulated community. This guidance explains the legal framework for the FQPA safety factor and key interpretations of statutory terms (See Appendix) and describes how the FQPA safety factor provision both formalizes and expands OPP's past practice of applying uncertainty factors to account for deficiencies in the toxicological database. Because this guidance only addresses the statutory provisions of FQPA, it does not apply to any of the Agency's other regulatory programs or risk assessment processes which are carried out under different statutory authorities. As explained below, this guidance explains how OPP intends to take into account potential pre- and post-natal toxicity and completeness of the data with respect to exposure and toxicity to infants and children as directed by FFDCA section 408(b)(2)(C)(i).