The 1760 placard meaning is straightforward: the vehicle is carrying a Class 8 corrosive liquid that doesn’t fit any more specific chemical entry in the federal hazardous materials table. The four-digit number 1760 is the United Nations identifier for “Corrosive liquids, n.o.s.” — shorthand for “not otherwise specified” — and it’s recognized by the U.S. Department of Transportation as a catch-all for corrosive liquids that lack their own dedicated UN number.1CAMEO Chemicals. UN/NA 1760 In plain terms, the cargo is a liquid that can destroy skin tissue on contact and corrode metal.
What UN 1760 Actually Covers
Because 1760 is a catch-all, the substance behind the placard isn’t any one chemical. Products commonly shipped under this number include corrosive cleaning compounds, tree and weed killing liquids, ferrous chloride solutions, and chemical kits containing corrosive components.1CAMEO Chemicals. UN/NA 1760 Proprietary blends and mixed formulations that don’t match a listed chemical also travel under this entry.
Federal regulations don’t let shippers hide behind the generic label. On the shipping papers, the technical name of the actual hazardous ingredient has to appear in parentheses after the shipping name — something like “UN 1760, Corrosive liquid, n.o.s., (Octanoyl chloride), 8, II.”2eCFR. 49 CFR 172.203 – Additional Description Requirements If the cargo is a mixture, the technical names of at least the two most hazardous components must be listed. The placard itself, though, only carries the 1760 number, so the specific chemical isn’t visible from the roadside.
Why It’s a Class 8 Corrosive
Every substance shipped as UN 1760 falls into Hazard Class 8. Under 49 CFR 173.136, a material qualifies as corrosive if it causes irreversible damage to human skin at the point of contact within a specified time, or if it severely corrodes steel or aluminum.3eCFR. 49 CFR 173.136 – Definitions Class 8 covers both acids and alkaline substances, and both can inflict severe chemical burns on contact.
The placard design reflects that hazard. It shows liquid pouring from test tubes onto a hand and a metal surface, with a black lower portion, a white triangle on top, black symbols and inner border, and white text and class number.4eCFR. 49 CFR 172.558 – CORROSIVE Placard The 1760 appears in the center of that graphic.
Packing Groups: How Dangerous the Liquid Actually Is
The 1760 designation alone doesn’t tell you how aggressive the corrosive is. That comes from the packing group, a Roman numeral assigned under 49 CFR 173.137 and listed on the shipping papers:
- Packing Group I is the most dangerous. It causes irreversible skin damage within 60 minutes of observation after three minutes or less of exposure.
- Packing Group II causes irreversible skin damage within 14 days of observation after more than three minutes but no more than 60 minutes of exposure.
- Packing Group III causes irreversible skin damage within 14 days after more than 60 minutes but no more than four hours of exposure. A material also qualifies for Group III if it corrodes steel or aluminum faster than 6.25 millimeters per year at a test temperature of 55°C, even without damaging skin.
The packing group drives container thickness, cushioning, and how closely the load can sit next to other hazardous cargo.5eCFR. 49 CFR 173.137 – Class 8 Assignment of Packing Group A Packing Group I 1760 shipment is treated very differently from a Packing Group III one.
When the 1760 Placard Must Be Displayed
Under 49 CFR 172.504, any vehicle carrying 454 kilograms (1,001 pounds) or more of a Class 8 material listed in Table 2 has to display the corrosive placard. Bulk packaging of any quantity triggers the placarding requirement regardless of weight.6eCFR. 49 CFR 172.504 – General Placarding Requirements Placards go on each side and each end of the vehicle, so the warning is visible from any angle of approach. Smaller quantities of the same material may travel without a placard, which is worth knowing: the absence of a 1760 placard doesn’t guarantee the absence of a corrosive liquid inside, only that any corrosive load is below the threshold.
What to Do Around a 1760 Vehicle in an Accident or Leak
If a truck or trailer showing the 1760 placard is involved in a crash or is visibly leaking, the 2024 Emergency Response Guidebook directs responders to Guide 154, which covers toxic and corrosive non-combustible substances.1CAMEO Chemicals. UN/NA 1760 The ERG’s general guidance calls for an isolation zone of at least 100 meters (330 feet) in all directions around a spill. For large spills, an initial downwind evacuation of at least 800 meters — roughly half a mile — should be considered.7Pipeline and Hazardous Materials Safety Administration. 2024 Emergency Response Guidebook
For an ordinary driver or bystander, the response is simple. Stay upwind. Keep your distance. Call 911. Corrosive liquids can give off harmful fumes, and a puddle spreading from one of these shipments is not something to step in, walk through, or drive through. Standard clothing offers no meaningful protection against a Class 8 liquid, and the exact chemical inside a 1760 load isn’t identifiable from the placard — only the emergency responders working from the shipping papers will know what it is.
The Short Version
A 1760 placard tells you three things at a glance. The cargo is a liquid. It’s corrosive enough to fall under DOT Class 8. And it’s a chemical that doesn’t have its own UN number, so it could be any of a wide range of acids, bases, or mixed formulations. Everything more specific — the exact substance, its packing group, its emergency contact — lives on the paperwork inside the cab, not on the sign on the outside.