NAICS 324121

Overview

The North American Industry Classification System (NAICS) is the U.S. government’s standard for classifying business establishments to support consistent statistical collection, analysis, and publication across the economy. Established under the Office of Management and Budget and adopted in 1997 to replace SIC, NAICS is maintained jointly by the U.S., Canada, and Mexico; the current structure is the 2022 vintage. ¹

NAICS 324121 covers establishments primarily engaged in manufacturing asphalt and tar paving mixtures and blocks from purchased asphaltic materials. It sits within the NAICS 32412 industry group (Asphalt Paving, Roofing, and Saturated Materials Manufacturing) in the Manufacturing sector. Activities that refine crude petroleum to produce paving materials fall under NAICS 324110. ²

What this NAICS covers

• Manufacture of asphalt paving mixtures from purchased asphaltic materials. ²
• Manufacture of tar paving mixtures from purchased asphaltic materials. ²
• Manufacture of asphalt paving blocks. ²
• Manufacturing activity within the asphalt paving, roofing, and saturated materials industry group, distinct from petroleum refining. ²
• Establishments whose primary output is paving mixtures or blocks, not roofing cements or coatings (those are under NAICS 324122). ²

Related NAICS and PSC codes

Cross-references and exclusions (official)

• Operations that refine crude petroleum and manufacture asphalt or tar paving mixtures/blocks are classified in NAICS 324110, not NAICS 324121. ²
• Roofing cements, coatings, and saturated mats/felts from purchased asphaltic materials are classified in NAICS 324122, not NAICS 324121. ²

Frequently asked questions

• What is the official definition of NAICS 324121?

  • NAICS 324121 comprises establishments primarily engaged in manufacturing asphalt and tar paving mixtures and paving blocks from purchased asphaltic materials. It is part of the NAICS 32412 industry group within Manufacturing and is defined distinctly from petroleum refining activities. ²

• How does NAICS 324121 differ from NAICS 324122?

  • NAICS 324121 covers paving mixtures and blocks. NAICS 324122 covers saturating materials (mats/felts) with asphalt or tar and manufacturing roofing cements and coatings from purchased asphaltic materials. The split turns on whether the output is paving mixtures/blocks versus roofing/saturating products. ²

• Does NAICS 324121 include petroleum refining activities?

  • No. If an establishment refines crude petroleum and manufactures asphalt or tar paving materials, it is classified under NAICS 324110 (Petroleum Refineries). NAICS 324121 applies when paving mixtures or blocks are made from purchased asphaltic materials, without crude oil refining. ²

• Which PSC code is commonly associated with asphalt paving mixtures in federal purchasing?

  • PSC 5610 (Mineral Construction Materials, Bulk) expressly includes asphalt and is often used to categorize bulk construction materials, including asphalt and related paving aggregates, in federal procurement and reporting. Agencies should confirm specific line-item descriptions when mapping requirements to PSCs. ³

• What is the current NAICS vintage used by federal statistical agencies?

  • The current NAICS structure is the 2022 vintage. The U.S. Census Bureau’s NAICS site provides the 2022 search and structure, while OMB oversees governance and update cycles in coordination with Canada and Mexico. Users should reference the 2022 codes for classification consistency. ¹

Useful resources

• G2X — NAICS 324121 overview
• U.S. Census Bureau — NAICS Introduction and 2022 search (official NAICS background and current vintage). ¹
• U.S. Census Bureau — 2022 NAICS Sector 31–33 Manufacturing page (context for manufacturing sector data and references). ⁴
• Acquisition.gov — Product and Service Code (PSC) Manual (April 2025), including definitions for PSC 5610 and related classes. ³
• U.S. Census Bureau — NAICS 32412/NAICS 324121 industry descriptions and cross-references (Manufacturing sector details). ²

References

1. U.S. Census Bureau, North American Industry Classification System (NAICS) — Introduction and 2022 Search. https://www.census.gov/naics/?input=ec&year=2022
2. U.S. Census Bureau, 2022 NAICS Sector 31–33 (Manufacturing) — Industry descriptions including 32412, 324121, cross-references. https://www.census.gov/naics/resources/archives/sect31-33.html
3. General Services Administration, Product and Service Codes (PSC) Manual, April 2025. https://www.acquisition.gov/sites/default/files/manual/PSC%20Manual%20April%202025.pdf
4. U.S. Census Bureau, 2022 NAICS Sector 31–33 — Manufacturing (Economic Census data). https://www.census.gov/data/tables/2022/econ/economic-census/naics-sector-31-33.html