North American Industry Classification System (NAICS) 1997
- 23 - Construction
- 231 - Prime Contracting
- 2313 - Engineering Construction
- 23131 - Highway, Street and Bridge Construction
- 231310 - Highway, Street and Bridge Construction
- 23132 - Water and Sewer Construction
- 231320 - Water and Sewer Construction
- 23133 - Oil and Gas Pipelines and Related Industrial Complexes Construction
- 231330 - Oil and Gas Pipelines and Related Industrial Complexes Construction
- 23139 - Other Engineering Construction
- 231390 - Other Engineering Construction
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