In Reply Refer To:

Mail Stop 412                                   January 9, 2002


Office of Water Quality Technical Memorandum 2002.05

Subject:   Approval of Laboratories with existing National Environmental Laboratory Accreditation Conference (NELAC) accreditation.




Office of Water Quality Technical Memorandum 98.03 discusses the approval process and responsibilities for accepting analytical work from an outside laboratory.  When a U.S. Geological Survey (USGS) District chooses to use a laboratory other than our national laboratories, the laboratory must prove that they can provide comparable data to those in our national database.


The process to ascertain that data are acceptable for the USGS is two-fold.  The first involves the Laboratory Evaluation Project (LEP), which reviews the Quality System of a laboratory.  Proper documentation, along with identified and quantifiable quality-control (QC) and quality-assurance (QA) practices provide the formula for acceptable data generation. Secondly, the Standard Reference Sample (SRS) project provides biannual reference materials to laboratories to assure that specific analyses are operating within an acceptable range. Together, the laboratory QA processes and the laboratory analytical results (QC) provide the USGS with an overall assurance of quality data.


Previously, environmental laboratories had to prove analytical proficiency to multiple customers with differing criteria for acceptance.  It was not uncommon that a laboratory had to participate in three or four different complete laboratory audits per year, all with slightly different requirements. The National Environmental Laboratory Accreditation Conference (NELAC) was formed to try to establish mutually acceptable performance standards for the inspection and operation of environmental laboratories. 




USGS would like to benefit from this consolidation of effort, and to minimize redundancy in the laboratory approval process. Therefore, USGS will recognize NELAC accreditation of laboratories for their quality-systems assessment and no longer require an independent USGS review. NELAC accreditation will suffice for USGS laboratory quality systems approval. Specific analyte performance proficiency is tested separately from laboratory quality system approval, and is still required for USGS.


The NELAC proficiency test sample results can be used to supplement USGS analyte performance evaluation.  However, analysis of USGS standard reference samples (SRS) will remain a necessary prerequisite for USGS approval. This is because proficiency test samples are aimed at satisfying specific regulatory program data quality objectives, and are not geared towards USGS ambient monitoring or in real matrices (they are usually spiked in laboratory reagent grade water). .


For a LABORATORY to be approved by USGS:


1. If a laboratory is NELAC certified, the USGS requirements for general documentation are satisfied and the laboratory is approved providing:

a.         The laboratory is certified for similar analyses as those of interest to the USGS;

b.         The list of deficiencies found by the NELAP accrediting authority is either resolved or in an acceptable state to the USGS; and

c.         There have been no significant changes in performance or operation that would change any previous findings.

2. To verify that the laboratory of interest is acceptable to USGS, we will require an amended list of documents for laboratory approval.

a.   The complete NELAC deficiency log from the NELAC on-site laboratory inspection. Include the laboratory response and corrective actions report.

b.   The NELAC proficiency sample results for at least two consecutive test periods.

c.   The requested analytes and concentrations ranges that need to be covered for the USGS project.

d.   SOPs of analyses for which the laboratory is NOT NELAC accredited.


For approval of SPECIFIC ANALYTES from a USGS approved Laboratory:


1.   Approval for specific analytes are USGS approved if they are NELAC accredited under the correct program.

a.   NELAC accreditation can be under either the Clean Water Act (CWA) or the Safe Drinking Water Act (SDWA) for USGS approval.

b.   USGS cannot accept accreditation under the CAA (Clean Air Act) for water samples.

c.   USGS cannot accept accreditation under the Resource Conservation and Recovery Act (RCRA) and Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA - commonly known as Superfund) for USGS analyses at ambient concentrations unless the ability to provide appropriate results in the expected concentration range and the appropriate matrix is proven.


2.   For NELAC accredited Inorganic analyses, participation in the USGS standard reference (SRS) project is still required.


3.   For NELAC accredited Organic, Radiochemical, Physical Measurements, and Biological analyses, participation in the USGS standard reference (SRS) project is not required if proficiency test samples are acceptably analyzed.


4.   If a laboratory has NELAC accreditation and USGS requires proof of proficiency for analytes that are not within the scope of its NELAC accreditation, the laboratory must provide appropriate SOPs to the USGS, and prove that these other analyses remain under the general Quality System accredited by NELAC audit.


Once a laboratory is approved by USGS, the specific analytes of interest must remain in an acceptable status as determined by performance on SRS and/or appropriate proficiency test samples. NELAC laboratory approvals are based on a 12-month period, and must be maintained in order to extend beyond 12 months.  USGS approvals are good for three years or until NELAC accreditation is revoked or performance is unacceptable and deemed irreparable in an appropriate time frame.





                           Stephen K. Sorenson

                           Acting Chief, Office of Water Quality


Distribution:  A, B, FO, PO

                District and Regional Water Quality Specialists


This memorandum is an amendment to Office of Water Quality Technical Memorandum 98.03.