Certifications and External Audits. Since the early 1990s, the National Environmental Laboratory Accreditation Program (NELAP) has promoted national standards for quality procedures that relate to laboratory certification. The NWQL has taken part in the NELAP process since 1995, and the NWQL's quality systems have been redesigned to comply with standards developed by The NELAC Institute (TNI). The NWQL is currently accredited through the States of New York, Florida, Texas, and North Carolina. These standards apply to all NWQL procedures used to obtain analytical data of known quality, a thorough and complete Quality Assurance Manual, and on-site audits.