DOT hazmat placarding requirements by hazard class (any-quantity vs. 1,001 lb threshold)

A shipment of hazardous material must be placarded on the transport vehicle, and which placard applies -- and whether it is required at any quantity or only once the aggregate gross weight of that class crosses 1,001 lb (454 kg) -- is fixed by two tables in one regulation, 49 CFR 172.504(e). Table 1's eight categories (explosives 1.1-1.3, poison gas, dangerous-when-wet, temperature-controlled organic peroxide, poison-inhalation-hazard, radioactive) require the named placard regardless of quantity. Table 2's fifteen require it only above 1,001 lb -- but that exception is a highway/rail exception that does not reach bulk packagings, which need a placard at any quantity, so every record carries the general rule and the exception's own scope alongside the number. Each record is one hazard-class / placard pairing. Answers 'do I need to placard this shipment', 'how much of this hazard class triggers a placard', 'which placard goes with hazard class 5.1'.

The data

Where this came from

Every record above links the page it was taken from and quotes the sentence that states it. These are the 1 source this dataset was assembled from.

• ecfr.govhttps://www.ecfr.gov/current/title-49/section-172.504

Machine-readable

• data.jsonThe whole dataset — every record with its source URL and source quote.
• Open Knowledge Format bundleOne JSON object per line — every record's frontmatter and quoted span exactly as it is held here, in one fetch.
• data.csvThe same records as one flat table, for a spreadsheet or a dataframe. The last four columns are the source URL, the quoted sentence it was read from, the date we last checked it, and which columns are our reading rather than the page's words.
• How this is made and checkedWhat "verified against source" does and does not mean.

From your own code

Same records, same quotes, without scraping the page: refsource is on PyPI and npm. Each value comes back carrying the URL it was read from and the sentence on that page that states it — .source and .quote sit on the value itself rather than in a side channel, so the checking step is available instead of skipped.

pip install refsource
refsource lookup dot-hazmat-placarding-thresholds placard_name="EXPLOSIVES 1.1"

npx -y refsource lookup dot-hazmat-placarding-thresholds placard_name="EXPLOSIVES 1.1"

Set your AI assistant up to use this

Two files and no account. Put this in .mcp.json at the root of your project — Claude Code, Cursor, Windsurf, VS Code and Codex all read that file — and your assistant can look this dataset up instead of recalling it. The server is remote, keyless and read-only.

{
  "mcpServers": {
    "referencesource": {
      "type": "http",
      "url": "https://referencesource.org/mcp"
    }
  }
}

Add to Cursor · or, on the command line: claude mcp add --transport http referencesource https://referencesource.org/mcp --scope project

Then one line in the project's CLAUDE.md or AGENTS.md, so the assistant knows when to reach for it:

When a question needs "DOT hazmat placarding requirements by hazard class (any-quantity vs. 1,001 lb threshold)", call the referencesource MCP server at https://referencesource.org/mcp (tool `search_records`, dataset_slug `dot-hazmat-placarding-thresholds`) instead of answering from memory — every record it returns carries its source URL and a verbatim quote from that page.

What each tool does, and the servers built over single registers: Connect your AI assistant.

23 records. last verified against source 2026-09-16. due for re-check by 2027-02-15.

Licence. US federal regulation — 17 USC 105, no copyright