Ask a warehouse team whether a drum of pure methanol and a case of windshield washer fluid carry the same shipping paperwork, and the honest answer is usually a guess. Methanol dangerous goods classification is one of the few entries in the Hazardous Materials Table where the pure chemical is fixed — UN1230, Class 3, subsidiary risk 6.1, packing group II, full stop — while the diluted consumer products built from it are classified on their own terms entirely.
This guide sets out that split precisely: what stays fixed, what varies with the finished blend, and where the toxic subsidiary risk actually bites.
Why methanol carries two hazards at once
Methanol burns. Its flash point sits at roughly 11–12°C, well inside the Class 3 flammable liquid band, which is unremarkable among solvents — ethanol, acetone and isopropyl alcohol all clear the same bar. What sets methanol apart is that it is also acutely toxic, and that toxicity is assigned as a subsidiary risk under Class 6.1 based on established regulatory precedent rather than a threshold you could calculate from a flash point or a boiling point. As industry classification guidance puts it plainly: a person cannot remove the 6.1 subsidiary class from methanol's shipping description. It travels with the entry.
That toxicity is not an abstract regulatory footnote. In August 2026, tainted alcohol killed 13 people and blinded another 21 in Kuwait, the latest in a run of methanol poisoning outbreaks from counterfeit and illegally produced spirits that has run through Jordan, Turkey and Southeast Asia over the past two years. Those deaths come from drinking adulterated alcohol, not from a freight incident — but they are the exact chemistry the subsidiary 6.1 risk exists to flag: methanol metabolises in the body to formaldehyde and then formic acid, and a dose that looks survivable can cause blindness or death within hours. A shipping classification that dropped the toxic risk because the flammability numbers were unremarkable would be missing the more dangerous half of the story.
Methanol dangerous goods classification at a glance: UN1230
| Field | Value | Note |
|---|---|---|
| UN number | UN1230 | Same across 49 CFR, IATA DGR and IMDG |
| Proper shipping name | Methanol | Also written as methyl alcohol or wood alcohol on some SDS documents |
| Hazard class | 3 (6.1) | Flammable liquid, toxic subsidiary risk |
| Packing group | II | Fixed for the pure substance entry |
| Labels | Class 3 flammable liquid, Class 6.1 toxic | Both labels required, primary and subsidiary |
| ERG guide | 131 | Emergency response guide reference |
Compare that fixed packing group against the classes and entries where the group genuinely moves with the batch — see hazardous goods categories and packing groups I, II and III for how that variability is built into the regulations for other entries.
Pure methanol versus a methanol-based blend
This is the split that trips up sellers who reason from the ingredient list rather than the finished product, and it is the part of methanol dangerous goods classification that a generic Class 3 checklist will not catch. Reagent-grade or fuel-grade methanol, shipped as itself, is UN1230 every time — packing group II is not a question. But methanol rarely reaches a parcel network in that form. It reaches it as an ingredient: windshield washer fluid, gas-line antifreeze sold as a fuel additive, fondue and camp-stove fuel, some paint strippers and denatured alcohol blends.
Those finished products are not classified against the UN1230 entry's fixed packing group. They are classified against the general Class 3 criteria — flash point and, where relevant, initial boiling point — applied to the blend as sold, under a generic entry such as alcohols, n.o.s. or flammable liquid, n.o.s. rather than under the name "methanol" itself. Two consequences follow, and both catch people out.
- A product can be mostly water with a modest methanol fraction and still meet the flammable liquid criteria, because methanol's own flash point is low enough that even a diluted blend can sit well under the Class 3 threshold.
- The packing group for that blend is not derivable from the methanol percentage on the label. It comes from a measured flash point on the finished formulation's own SDS, and formulations at broadly similar methanol content can land in different packing groups depending on the rest of the mixture.
| Flash point | Packing group | Typical result |
|---|---|---|
| Below 23°C, boiling point 35°C or below | I | Rare for a diluted consumer blend |
| Below 23°C, boiling point above 35°C | II | Concentrated washer fluid, camp-stove fuel |
| 23°C up to 60°C | III | Typical retail windshield washer fluid |
| Above 60°C | Not Class 3 | Heavily diluted, low-methanol formulations |
Our guide to reading an SDS for classification covers exactly which section carries this flash point figure and how to avoid pulling the wrong number from a supplier document.
When a "summer" reformulation changes the paperwork
An automotive accessories brand ships a winter-grade windshield washer fluid at a methanol concentration strong enough to sit in packing group III, correctly labelled and boxed for years without incident. Heading into a warmer sales region, the brand's chemist reformulates a summer-grade version, cutting the methanol fraction to reduce cost and odour, on the reasonable assumption that less methanol means less regulation, not more paperwork.
Nobody re-ran the flash point test on the new formulation before the first pallet shipped. It turned out the diluted blend still cleared the Class 3 threshold — the water-heavy mixture's flash point moved, but not far enough to exit flammable liquid territory — and the outer cartons, printed for the winter grade's already-correct packing group III marking, happened to still be right. The near miss was not the label; it was the assumption. A different summer reformulation from the same brand, cut further the following year to chase an even lower cost target, crossed the line the other way and stopped needing Class 3 markings altogether, and the warehouse kept applying them out of habit until a carrier audit flagged the shipment as over-declared.
Dilution is not deregulation, and it is not automatic regulation either. The flash point of the finished blend is the only fact that decides a Class 3 question, and it has to be measured on that blend, not inferred from what a stronger or weaker version of the same product did last year.
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The reportable quantity marking, separate from packing group
A complete methanol dangerous goods classification does not stop at the packing group. Bulk and industrial methanol shipments carry one more check that has nothing to do with packing group. Methanol has a CERCLA reportable quantity, and a package containing methanol at or above that threshold needs an RQ marking on the shipping paper and package in addition to the Class 3 (6.1) hazard labels — a requirement set by the quantity of methanol present, not by its concentration or its flash point. It is easy to satisfy the flammable-liquid classification correctly and still miss this marking, because the two checks run on different inputs and neither test implies the other. For the underlying Hazardous Materials Table entries and how a determination like this is built up field by field, see the eCFR's 49 CFR part 172.
Where carriers actually diverge
Getting the methanol dangerous goods classification right on paper is one thing; what a given service will actually carry, and how it treats the toxic subsidiary risk, is another.
- UPS and FedEx accept properly classified, packaged and labelled Class 3 (6.1) shipments on their ground networks, and within tighter limits on air, subject to their own dangerous goods acceptance rules for a flammable liquid with a toxic subsidiary risk.
- USPS treats methanol and methanol-based flammable liquids under Publication 52's hazardous materials rules, with quantity limits that are considerably tighter for anything carrying a toxic subsidiary risk than for a straightforward flammable liquid alone.
- Amazon FBA reviews flammable, toxic liquids as a restricted category rather than an automatic acceptance, and inbound shipments of methanol-based products commonly need hazmat review documentation before a fulfilment centre will take them.
By air, the entry sits within the IATA Dangerous Goods Regulations, and by sea within the IMO's IMDG Code — both carry the same UN1230 identity, but packing instructions, quantity limits and passenger-versus-cargo restrictions differ meaningfully by mode. Our carrier-by-carrier hazmat comparison sets these positions out side by side, and the Amazon FBA hazmat review guide covers what a flammable, toxic liquid submission actually needs to clear.
- Assuming a diluted methanol product ships under the fixed UN1230 packing group II, rather than checking the blend's own flash point.
- Reformulating toward a lower methanol content without re-running the flash point test, on the assumption that less is automatically safer to ship.
- Treating the Class 3 flammability determination as covering the whole classification and forgetting the 6.1 subsidiary risk cannot be dropped.
- Missing the RQ marking on a bulk industrial shipment because the packing group check alone was satisfied.
- Applying USPS's ordinary flammable-liquid limits to a product that also carries the tighter toxic-subsidiary-risk restrictions.
Checking your own SKU
The determination needs the same fields whether you are shipping the pure chemical or a formulated blend: the product's identity or composition, and for a blend, its own measured flash point from the SDS. Send that to POST /api/classify and you get UN1230 back for the pure substance, or the correct generic flammable-liquid entry and packing group for a diluted product, together with the per-carrier position for the service you plan to use.
For the wider picture of how flammable liquids sit alongside toxic and corrosive entries, see the nine classes of hazardous materials, or browse the encoded Class 3 entries to see what else shares the class. Pure and diluted methanol sit inside the same regulatory framework as every other flammable liquid — methanol dangerous goods classification is a fixed lookup for the chemical itself, and a flash point check for everything built from it.
