The Nat. Institute of Justice (NIJ) provides objective, independent, evidence-based knowledge and tools to meet the challenges of crime and justice, particularly at the State and local levels. The Office of Law Enforcement Standards (OLES) of the NIST furnishes technical support to NIJ in the development of standards. OLES subjects existing equipment to laboratory testing and evaluation and conducts research leading to the development of nat. standards, user guides, and technical reports. This document covers research conducted by OLES. It includes information on the selection of personal protective equipment (PPE) that includes chemical and biological protective clothing and respiratory equipment for different applications.