NFPA 704 fire diamond ratings by chemical
The NFPA 704 'fire diamond' rating for a chemical — the health (blue), flammability (red), instability (yellow) numbers and any special (white) notice — as published on that chemical's own datasheet. Each record is one chemical, with the four quadrants and the datasheet's own wording for what each value means. Answers 'what is the NFPA 704 rating for anhydrous ammonia', 'fire diamond numbers for thionyl chloride', and 'what does a 3 in the blue diamond mean'. NFPA 704 itself is a paywalled standard and the per-chemical ratings are scattered one page at a time across datasheets and SDSs, so no single free table exists — assembly, one source per record.
The data
| Chemical | CAS number | Health (blue) | Flammability (red) | Instability (yellow) | What the rating means | Special (white) |
|---|---|---|---|---|---|---|
| AMMONIA, ANHYDROUS | 7664-41-7 | 3 | 1 | 0 | Health | 3 | Can cause serious or permanent injury. | Flammability | 1 | Must be preheated before ignition can occur. | Instability | 0 | Normally stable, even under fire conditions. | Special | | | Note: The Refrigeration System Classification section of the International Mechanical Code requires a value of 3 for the red quadrant (flammability hazard) for indoor ammonia refrigeration equipment. | |
| AMMONIUM NITRATE-PHOSPHATE MIXTURE | 57608-40-9 | 0 | 0 | 3 | Health | 0 | No hazard beyond that of ordinary combustible material. | Flammability | 0 | Will not burn under typical fire conditions. | Instability | 3 | Capable of detonation or explosive decomposition or explosive reaction but requires a strong initiating source or must be heated under confinement before initiation. | Special | OX | Possesses oxidizing properties. | Note: NFPA ratings shown are for ammonium nitrate, CAS number 6484-52-2. | OX |
| CYCLOPROPANE | 75-19-4 | 1 | 4 | 0 | Health | 1 | Can cause significant irritation. | Flammability | 4 | Burns readily. Rapidly or completely vaporizes at atmospheric pressure and normal ambient temperature. | Instability | 0 | Normally stable, even under fire conditions. | Special | | | | |
| THIONYL CHLORIDE | 7719-09-7 | 4 | 0 | 2 | Health | 4 | Can be lethal. | Flammability | 0 | Will not burn under typical fire conditions. | Instability | 2 | Readily undergoes violent chemical changes at elevated temperatures and pressures. | Special | W Reacts violently or explosively with water. | W |
Where this came from
Every record above links the page it was taken from and quotes the sentence that states it. These are the 4 sources this dataset was assembled from.
- cameochemicals.noaa.govhttps://cameochemicals.noaa.gov/chemical/4860
- cameochemicals.noaa.govhttps://cameochemicals.noaa.gov/chemical/100
- cameochemicals.noaa.govhttps://cameochemicals.noaa.gov/chemical/500
- cameochemicals.noaa.govhttps://cameochemicals.noaa.gov/chemical/1600
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 nfpa-704-hazard-ratings chemical="AMMONIA, ANHYDROUS"
npx -y refsource lookup nfpa-704-hazard-ratings chemical="AMMONIA, ANHYDROUS"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 "NFPA 704 fire diamond ratings by chemical", call the referencesource MCP server at https://referencesource.org/mcp (tool `search_records`, dataset_slug `nfpa-704-hazard-ratings`) 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.