The Clean Air Act (CAA) requires EPA to regulate compounds that are listed as air toxics, also known as hazardous air pollutants. Air toxics are those pollutants known, or suspected, to cause cancer and other human health problems. The law allows EPA to consider petitions to modify the list, by adding or removing substances. Individuals seeking to add a substance must demonstrate the substance is an air pollutant and that emissions, ambient concentrations, bioaccumulation or deposition of the substance are known to cause or may reasonably be anticipated to cause adverse effects to human health or adverse environmental effects. The Agency received a petition to add n-Propyl Bromide from the Halogenated Solvents Industry Alliance in October 2010. Once EPA receives a petition, it conducts two reviews: a completeness review, to determine whether there is sufficient information on which to base a decision; and a technical review, to evaluate the merits of the petition. This action will conduct the completeness review to determine if the Solvents Industry Alliance's petition of October 2010 is complete based on the requirements of the CAA. The petition was determined to be complete by the work group, and a completeness notice will be published in the Federal Register w/OAR signature.