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Environmental Laboratory (NELAP) Accreditation

This page offers information on the Agency's National Environmental Laboratory Accreditation Program (NELAP)

Laboratories are assessed against the provisions of the 2009 TNI NELAP standards.


The Texas Commission on Environmental Quality will be hosting its 2018 Environmental Trade Fair and Conference on May 15-16, 2018 at the Austin Convention Center.  As usual, this will include the Lab Practices and Data Reporting track. 

You can find more information, including a tentative agenda, at the Environmental Trade Fair and Conference (ETFC) link

1)  Effective on June 01, 2017, the accreditation Application has been updated to explicitly list DOC/MDL data as required documentation for new or amendment applications.


2)  Based on the increase in repeat deficiencies from laboratories, the TCEQ’s Laboratory Accreditation Program review process for evaluating laboratories’ corrective action responses (CARs) to accreditation assessments was revised. 

The TCEQ has revised the corrective action response form, which is attached to assessment reports.

The form has four main sections:

  • Corrective Actions to Address the Deficiency
  • Actions to Prevent Recurrence of the Deficiency
  • Client Notification
  • Verification of Effectiveness

For each section, the laboratory must provide the action(s), the timetable(s), and the means to document.

Use of the form is not mandatory.  However, all the information requested on the form is needed to evaluate the laboratory’s corrective action response regardless of the format.

The form can be found on the Laboratory Resources section of this web page or directly here: CAR form(Word)


Subscribe to Laboratory Accreditation Program e-mail updates

Go to this link: Get e-mail updates on your choice of topics.

After entering your e-mail address and personal preferences, mark the Laboratory Accreditation / Environmental Laboratory (NELAC) Accreditation box.


Application, Fields of Accreditation, Checklists, and Procedures

Application (PDF) (Revision 9 - June 2017)

Fields of Accreditation (FoAs) (PDF) (Revision 17 - October 2016)


History of changes to the Fields of Accreditation (PDF)


The current list of accredited laboratories, with links to their scope of accreditation, can be accessed here:

List of Accredited Laboratories (PDF)


The accreditation team uses the 2009 TNI Quality Systems checklist Exit the TCEQ to determine each laboratory's conformance to the elements of this Standard. A copy of the TNI checklist is now available directly from their web page.

Be advised that you must have a copy of the TNI Standard ELV1, Management and Technical Requirements for Laboratories Performing Environmental Analyses before you may download this checklist.


TCEQ (Internal) Accreditation Procedures (PDF)


Accreditation applications in progress (PDF)


For administrative information, please contact our records specialist at 512/239-3754 or e-mail us at labprgms@tceq.texas.gov.


For additional information, including suitable ways to obtain traceability of measurements, or to make a complaint, please contact the program manager at 512/239-1990 or e-mail us at labprgms@tceq.texas.gov.


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Laboratory Resources

FAQ guides.  This is a document addressing frequently asked questions regarding the Texas laboratory accreditation program:

FAQ guides (PDF)


Corrective Action Response (CAR) form.

CAR form (Word)

Corrective Action Response Guidelines For TCEQ Accredited Laboratories (Presentation from 2017 Trade Fair) (Powerpoint)


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External Links


The NELAC Institute (TNI) Exit the TCEQ


National Environmental Laboratory Accreditation Program (NELAP) designated proficiency testing providers Exit the TCEQ


NELAP Fields of Proficiency Testing Exit the TCEQ


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Our mailing address is:

Texas Laboratory Accreditation Program
Texas Commission on Environmental Quality
P.O. Box 13087, MC-165
Austin, TX 78711-3087


Our physical address for overnight mail delivery is:

Texas Laboratory Accreditation Program
Texas Commission on Environmental Quality
12100 Park 35 Circle, Bldg B, MC-165
Austin, TX 78753


Rules (Including Fees) and Accreditation Standards

Title 30, Texas Administrative Code, Chapter 25 Exit the TCEQ, Subchapters A and B (for a schedule of fees refer to §25.30)



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