The Clean Air Act (CAA) requires the EPA to regulate compounds that are listed as air toxics, also known as hazardous air pollutants (HAP). Air toxics are those pollutants known, or suspected, to cause cancer and other serious human health problems. The CAA allows the 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 two petitions to add n-Propyl Bromide to the HAP list from the Halogenated Solvents Industry Alliance in October 2010 and from the State of New York in November 2011. Once the EPA receives a petition, it conducts two reviews: (1) a completeness review, to determine whether there is sufficient information on which to base a decision; and, (2) a technical review, to evaluate the merits of the petition. The petitions were determined to be complete and a notice of receipt of a complete petition was published in the Federal Register on 2/6/15. This action addresses the technical review of the petitions based on the CAA section 112(b)(3) requirements.