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Environmental Laboratory (NELAP) Accreditation

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

Effective January 31, 2020, laboratories are assessed against the provisions of the 2016 TNI NELAP standard.

Please see link for summary of changes below.

Changes to the various standards used in the National Environmental Laboratory Accreditation Program (NELAP) (PDF)


COVID-19 Response procedures

UPDATE 2 (replaces Update 1.1):

Laboratory accreditation staff have switched to a hybrid work schedule with the bulk of the time spent working remotely.  Therefore, to ensure submitted documents are available for processing as expeditiously as possible, we are requesting laboratories continue to adhere to the following until further notice:

1.  Submit all laboratory accreditation payments to TCEQ revenue section at the following address.  Do not submit them directly to the TCEQ Laboratory Accreditation Program.

Texas Commission on Environmental Quality
Cashier's Cage
P.O. Box 13088, MC-214
Austin, TX 78711-3088

Their physical address for overnight/non-US mail deliveries is:

Texas Commission on Environmental Quality
Cashier's Cage
12100 Park 35 Circle
Austin, TX 78757

2.  Submit all laboratory accreditation-related documents electronically.  There is no need to follow up with hard copies.

3.  If you do not know the e-mail address of the individual recipient, please use the mailbox, which is being monitored in real time during regular office hours. 

4.  Laboratory accreditation staff will not have immediate access to their phones.  They will be checking their messages periodically; however, there may be a delay in a response.  If possible, send an email message in conjunction with the voice message as staff have immediate access to their emails.  In addition, staff will be monitoring and responding to email messages sent to

5.  Laboratories will receive electronic copies of their certificates and scopes.  Hard copies will not be mailed.

If you have any questions about these directives, please contact TCEQ Laboratory Accreditation Program (TCEQ LAP) at

TCEQ LAP encourages laboratories to ensure the safety of their employees and understands there may be some disruptions to normal operations.  Any laboratories that are closing due to COVID-19 need to notify TCEQ LAP as soon as possible.  In addition, TCEQ will evaluate situations where a laboratory is unable to fulfill any requirements in the standard due to disruptions from COVID-19 on a case-by-case basis.

TCEQ will be providing updates on our web page and through our laboratory GovDelivery email notification system as the situation changes.

Subscribe to Laboratory Accreditation Program e-mail updates

Go to this link: Get email or text updates on your choice of topics.

After entering your email address or phone number, select “Environmental Laboratory Accreditation” from the list. You can unsubscribe any time.

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Application, Fields of Accreditation, Checklists, and Procedures

Application (PDF) (Revision 10 - February 2020)

Fields of Accreditation (FoAs) (PDF) (Revision 18 - April 2019)

Technical Manager Qualification Form (PDF) (Revision 1, fillable - October 2023)

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 (Word)

The accreditation team uses the 2016 TNI Quality Systems checklist 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 (2016) before you may download this checklist.

TCEQ (Internal) Accreditation Procedures (PDF)

Accreditation applications in progress (Word)

For administrative information, please contact our records specialist at

For additional information, including suitable ways to obtain traceability of measurements, or to make a complaint, please contact the program manager at

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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 (Excel) (Revision 4 - October 2023)

CAR form instructions (PDF) 

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

MUR information

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External Links

The NELAC Institute (TNI)

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

NELAP Fields of Proficiency Testing

Link to the EPA Methods Update Rules web page

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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

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Rules (Including Fees) and Accreditation Standards

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

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