1. (a) The operator of an environmental testing laboratory applying for initial accreditation shall ensure that two proficiency test samples are successfully analyzed, if available, according to National Environmental Laboratory Accreditation Conference (NELAC) standards, for each requested field of accreditation.
2. (b) The operator of an accredited environmental testing laboratory shall ensure at least two proficiency test samples are analyzed, if available, each year for each field of accreditation according to NELAC standards. An environmental testing laboratory that does not meet the requirements of the subsection may participate in a supplemental proficiency test study according to the NELAC standards.
3. (c) The executive director shall determine the environmental testing laboratory's accreditation status for all affected fields of accreditation within 60 days of determining that laboratory personnel failed to analyze proficiency test samples successfully according to NELAC standards.
4. (d) Proficiency test samples, if available, shall be purchased from a National Environmental Laboratory Accreditation Program designated provider.

Source Note:The provisions of this §25.20 adopted to be effective September 12, 2002, 27 TexReg 8480.