SIC 4491 — Marine Cargo Handling
Official OSHA SIC Manual Definition
Establishments primarily engaged in activities directly related to marine cargo handling from the time cargo, for or from a vessel, arrives at shipside, dock, pier, terminal, staging area, or in-transit area until cargo loading or unloading operations are completed. Included in this industry are establishments primarily engaged in the transfer of cargo between ships and barges, trucks, trains, pipelines, and wharfs. Cargo handling operations carried on by transportation companies and separately reported are classified here. This industry includes the operation and maintenance of piers, docks, and associated buildings and facilities; but lessors of such facilities are classified in Real Estate, Industry 6512.
Description & Classification
SIC code 4491 representing 'Marine Cargo Handling' is an industry category in the Standard Industrial Classification (SIC) system under U.S. OSHA and Federal procurement registers.
Modern NAICS Crosswalk
Trace the modern equivalent classifications in the 2022 North American Industry Classification System (NAICS) database:
- NAICS 488320 - Marine Cargo Handling (via SIC1987:4491→NAICS1997:48832→2002:488320→2007:488320→2012:488320→2017:488320→2022:488320)
- NAICS 488310 - Port and Harbor Operations (via SIC1987:4491→NAICS1997:48831→2002:488310→2007:488310→2012:488310→2017:488310→2022:488310)
Classification Details
| SIC Code | 4491 |
|---|---|
| Industry Title | Marine Cargo Handling |
| Division | Division E: Transportation, Communications, Electric, Gas, and Sanitary Services |
| Major Group | Major Group 44: Water Transportation |
| JSON Endpoint | View as JSON · API → |
| Source / Verified | US Census 1987 SIC Concordance / 2026-08-08 |
SIC vs NAICS Compliance & Common Mismatches
Legacy SIC code 4491 classifies commercial operations based on primary end-product or service output under the 1987 federal framework. In contrast, modern 2022 NAICS codes group establishments based on production process inputs.
When submitting public disclosures to SEC EDGAR or determining OSHA workplace safety log recordkeeping exemptions (29 CFR Part 1904), rely strictly on the official OSHA 4-digit SIC classification rather than an automated commercial translation.
💡 Expert Guidance: SIC to NAICS Conversion
Common Compliance Mistake: Many contractors and B2B analysts confuse legacy 4-digit SIC codes like 4491 with modern 6-digit NAICS codes. Ensure that you use the correct active 2022 NAICS code (e.g. from the crosswalk below) when submitting representations on SAM.gov, as federal contracting officers only accept modern NAICS codes.
Related Pages & Tools
Further regulatory reference links for legacy SIC code 4491:
- SIC Codes Complete Compliance Guide — Detailed history and active legal applications of the SIC classification framework.
- Why Legacy SIC Codes Persist Guide — How credit systems and the SEC still rely on SIC metadata.
- SIC ↔ NAICS Crosswalk Tool — Trace industrial code conversions dynamically.
- SIC 4491 to NAICS Crosswalk — Bidirectional mapping to modern NAICS codes (Marine Cargo Handling).
- SIC Code for Cargo Shipping — Standard Industrial Classification mapping details.
- SIC Major Group 44 Hub — View other legacy industries in this business division.
Frequently Asked Questions (FAQ)
What industry sector is represented by legacy SIC code 4491? ▾
Legacy SIC code 4491 represents 'Marine Cargo Handling', categorized under Division Division E: Transportation, Communications, Electric, Gas, and Sanitary Services and Major Group Major Group 44: Water Transportation. The Standard Industrial Classification (SIC) system was developed in the late 1930s.
What is the modern 2022 NAICS equivalent for legacy SIC 4491? ▾
Legacy SIC code 4491 maps to the modern 2022 NAICS industry classifications: NAICS 488320 (Marine Cargo Handling), NAICS 488310 (Port and Harbor Operations). Mappings are resolved transitively across successive updates to handle splits.
Why do credit agencies and banks still reference legacy SIC code 4491? ▾
Registries like Dun & Bradstreet, insurance underwriters, and private platforms retain SIC code 4491 because their historical financial risk data and scoring models are indexed using the legacy 4-digit SIC framework.
Does the SEC EDGAR system allow searching public filings by SIC 4491? ▾
Yes. The SEC Division of Corporation Finance assigns a primary 4-digit SIC code to public companies. You can search the EDGAR database using SIC code 4491 to group reporting peer firms.
How do OSHA safety recordkeeping rules apply to SIC code 4491? ▾
Under 29 CFR Part 1904 safety regulations, OSHA references legacy SIC codes including 4491 to determine if a physical establishment is required to maintain daily injury logs (Form 300) or is partially exempt.
What is the structural difference between SIC 4491 and NAICS codes? ▾
SIC code 4491 classifies establishments based on their final product output or market destination (what they sell), while modern NAICS codes classify them based on production processes and inputs (how they work).
What are the typical business activities classified under legacy SIC 4491? ▾
Typical business activities classified under legacy SIC 4491 are the operations associated with 'Marine Cargo Handling'. Mapped modern NAICS codes can be referenced for specific current examples.
Is legacy SIC code 4491 uniform across all 50 U.S. states? ▾
Yes, the Standard Industrial Classification (SIC) system, including code 4491, was published as a federal standard and remains uniform nationwide. It is still referenced by various state workers' compensation boards and departments of labor.
Sources & References
- U.S. Department of Labor (OSHA): OSHA Standard Industrial Classification (SIC) Manual — Code 4491
- U.S. Census Bureau: 1987 SIC to 2022 NAICS Concordance Tables
- Federal Reserve Board: Industrial Production & Capacity Utilization Classifications
- Internal Revenue Service (IRS): Schedule C Principal Business Activity (PBA) Industry Concordance
- Office of Management and Budget (OMB): Standard Industrial Classification Systems Governance