Challenge: Police officers, firefighters, and emergency medical technicians face many hazards on the job, including chemical, biological, radiological, and nuclear (CBRN) threats. Effective personal protective equipment and strict safety standards are critical to ensure the health and safety of emergency responders. Approach: Stakeholders from government, manufacturing and emergency response fields joined NIOSH to establish new respirator standards for CBRN hazards. They established performance requirements and identified concerns with the existing equipment development process, such as policy, manufacturing and personnel issues. This input allowed researchers to develop practical standards to protect workers from CBRN threats. Impact: This group effort resulted in the first CBRN standards for respirators. The u.s. Department of Homeland Security (DHS) adopted the new standards for all equipment purchased by DHS grant funds. The National Fire Protection Association also endorsed these standards. Approximately 7% of all on-duty career firefighters had CBRN respirators available or on order by December 2004. Additionally, six major equipment manufacturers have received approvals, and sixteen retrofit kits have also been approved.