The recommendations presented in this report are based on the assumption that officers who wear PPE will have a good understanding of chemical, biological, radiological, and nuclear hazards and be well-trained in the use of the equipment. The report focuses on helping law enforcement departments in PPE acquisition, application, and maintenance decisions. The report advises that respiratory protection is the most important piece of chemical-agent protection for responding officers. In order to determine whether a particular mask affords proper respiratory protection against various chemical agents, an extensive evaluation must be performed. References to the standards associated with respiratory protection are appended to this report. Regardless of the type of respirator used, it is recommended that a chemical protective hood be used in conjunction with it. One section of this report provides departments with a basic knowledge of the types of respirators available, their applicability to the law enforcement mission, the regulatory requirements for use of respirators, and the results of evaluations of respirators currently used by most law enforcement agencies. Another section of the report focuses on general operation considerations. The information and recommendations address initial response, scene security, perimeter security, security of critical infrastructure, and operations in the "warm zone." The concluding section provides guidelines for special planning considerations. These pertain to patrol officers operations, tactical team operations, and ensemble considerations. The report advises that each department must consider what roles it will perform in support of the overall response to a chemical attack, what actions must be handled by local authorities before State and Federal resources arrive, and what equipment requirements must be met to perform such missions. Officers must be trained in the proper use of PPE, including the limits of its protection. 15 tables and 10 appendices that provide supplementary information on protection requirements, chemical agents, decontamination operations, and safe duration times for personnel using PPE at the scene of a chemical attack