Southwestern Testing Laboratories, L.L.C.

Dallas, TX Doing business as STL Engineers

Company facts

Self-certified in SAM.gov: Minority Owned Business

For Profit Organization

Woman Owned Business

DOT Certified DBE

Limited Liability Company

Hispanic American Owned
Entity structure: Partnership or Limited Liability Partnership
Other NAICS codes in SAM.gov: 541350 Building Inspection Services

541380 Testing Laboratories and Services

541620 Environmental Consulting Services
SAM.gov registration date: Nov 30, 2005
Physical address: 535 Regal Row, Dallas, TX 75247, USA
Website: stlengineers.com
Industry: Industrials

Capital Goods

Construction & Engineering

Civil Engineering
SIC code: 87 Engineering & Management Services
Profiles: LinkedIn

Registration and certifications come from SAM.gov and the SBA; company details from public web sources. Updated May 25, 2026.

Vendor	Location	Primary NAICS
Llewellyn & Associates Inc. UEI QKBETJT32NB6	Knoxville, TN	541380 Testing Laboratories and Services
Driggers Engineering Services, Inc. UEI WL8RDYHXGQZ6	Clearwater, FL	541330 Engineering Services
Engen Consultants, Inc. UEI MSAUNQL57WP3	Temecula, CA	541330 Engineering Services
Mtgl Inc. UEI DHV5RDE4BFL5	San Diego, CA	541380 Testing Laboratories and Services
Gmts, PSC UEI H36DNKBJEBA7	San Juan, San Juan	541330 Engineering Services

From the vendor's SBA profile

Geotechnical, Material Testing

Yes. Southwestern Testing Laboratories, L.L.C.'s SAM.gov registration is active through May 21, 2027.

Southwestern Testing Laboratories, L.L.C.'s CAGE code is 47UH2, and its Unique Entity ID (UEI) is PJ9JDCJZ3MF3.

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