The guidelines describe quality-assurance activities that a laboratory should follow in ensuring the competency of the laboratory and the quality and integrity of its scientific data. The quality manual that describes the features of a lab's quality assurance procedures should address, at a minimum, goals and objectives, organization and management, personnel qualifications and training, facilities and security, sample control, validation, analytical procedures, calibration and maintenance, proficiency testing, corrective action, documentation and report writing, review of reports, safety, audit, and the monitoring of any subcontractor's work. For each of these basic features of a lab's quality assurance system, this report provides guidelines for lab policy and procedures. In addition to a manual that explains quality assurance guidelines, the lab should designate an individual to serve as the quality manager. The quality manager continuously monitors the implementation of all of the features of the quality assurance system. 8 references and definitions of terms used in the guidelines