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San Antonio Testing Laboratory LLC is a privately owned and locally operated testing facility that provides environmental and industrial analytical services. Tailored for private, corporate, and public needs, we offer fast response times and rigorous quality assurance. We are proudly a hispanic woman owned business that has been operating since 1987.


Our extensive experience assisting clients with routine testing and large scale contracts is paired with up-to-date technologies and techniques, allowing us to focus on client satisfaction and ever changing regulatory requirements, academic discoveries, and industry innovations. We take pride in our thorough quality control to ensure all data is accurate and meets strict protocols and inspections. To ensure accurate reports, this includes following sample collection, container, preservation, preparation, cleaning, and method standards from USEPA SW-846 and USEPA 600/4-79-020.


If you would like more information or have any questions, please contact us.

Accreditations & Certifications

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TCEQ NELAP Accredited 

Texas Commission on Environmental Quality NELAP certified laboratory.
TNI approved proficiency test sample for Water Pollution-Water Supply and Solid Waste matrices.

Certification No. T104704360


Texas HUB Certified

State of Texas Historically Underutilized Business Program Certified Minority Owned Business and Women Owned Business.

Certificate/VID No.1471089620100




South Central Texas Regional Certified Small, Minority, Woman- Owned, Hispanic-American, and Disadvantaged Business.

Certificate No. 220098942



Marcela Hawk


Over thirty years of financial, managerial, and personnel administration experience. More than twenty years laboratory management experience. Past Vice-Chairman and Program Director for the Alamo Laboratory Analyst Chapter of the Texas Water Utilities Association. Member of the Texas Water Utilities Association and San Antonio Manufacturer's Association.

BBA Management

Pan American University


Richard Hawk


Extensive thirty years of experience in laboratory management, operations and administration.

Past President of the Alamo Laboratory Analyst Association.

Past Chairman of the Lab Analyst's Section of the Texas Water Utilities Association and former Board Member for the San Antonio Manufacturer's Association.

Northern Michigan University

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Marissa Esquivel


Eight years of experience in laboratory project management and quality control. Experienced and trained in extraction and analysis of organics & inorganic pollutants and analytical instrumentation including GC, GC/MS, HPLC, IC, ICP, and ICP-MS. Extensively knowledgeable of QA/QC procedures, including NELAP & TNI, EPA SW-846 wastewater, drinking water as well as general methods. Knowledgeable on drinking water regulations with respect to public water systems.

Bachelor of Science in

Bioenvironmental Sciences

Texas A&M University

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