Flammable liquids are the workhorse hazard class of American freight. Paints, coatings, adhesives, solvents, fuels, cleaning products, fragrances — if your business makes or moves any of them, you are a Class 3 shipper whether you planned to be or not. Class 3 is also one of the most frequently cited classes in DOT enforcement, largely because so many shippers treat these products as ordinary freight.
This guide walks through how Class 3 shipments are classified, packaged, marked, and tendered by ground, air, and ocean, with practical notes for South Florida shippers moving product through Miami.
What counts as a Class 3 flammable liquid?
Under 49 CFR 173.120, a flammable liquid is a liquid with a flash point of not more than 60 °C (140 °F). The flash point — the lowest temperature at which the liquid gives off ignitable vapor — comes from the product’s Safety Data Sheet, and it drives everything downstream.
Common Class 3 entries include UN1263 (paint and paint-related material), UN1993 (flammable liquid, n.o.s.), UN1219 (isopropanol), UN1170 (ethanol solutions), and UN1866 (resin solution). Each pairs with a packing group based on flash point and initial boiling point: PG I for the most volatile liquids, PG II for flash points below 23 °C, and PG III for flash points between 23 °C and 60 °C.
Getting the packing group right matters because it sets the required packaging performance level, the quantity limits per package, and in some cases whether the shipment qualifies for limited quantity relief.
Packaging, marking, and labeling
Fully regulated Class 3 shipments require UN specification packaging tested to the packing group’s performance level — for example, a 1A1 steel drum or 4G fiberboard box with inner packagings, marked with the UN certification code. Closures must be installed per the closure instructions, and combination packagings need absorbent or cushioning where required.
Each package must display the proper shipping name and UN number, the Class 3 flammable liquid label, and orientation arrows on combination packagings with liquid inners. Shipments moving by vessel or air also need the technical name for n.o.s. entries.
Many retail-strength products qualify as limited quantities by ground, which trades the UN spec packaging and labels for the black-and-white “Ltd Qty” mark — but the relief has strict inner-packaging limits, and it changes again for air. If you’re unsure which side of the line your product falls on, a hazmat compliance review is the fastest way to find out before a carrier rejects the freight.
Ground, air, and ocean: how the rules shift
Ground (49 CFR)
By ground, Class 3 is broadly shippable, with placarding required at 1,001 lbs aggregate gross weight for most entries. Segregation is manageable, though flammables must stay clear of oxidizers and certain other classes on mixed loads.
Air (IATA DGR)
By air, quantity limits tighten sharply — PG I liquids may be capped at 1 L per package on passenger aircraft, and many entries are cargo-aircraft-only at higher quantities. A Shipper’s Declaration and IATA-trained personnel are mandatory.
Ocean (IMDG Code)
By ocean, Class 3 requires attention to stowage categories and segregation aboard the vessel, plus a signed Dangerous Goods Declaration and container packing certificate for containerized loads. Out of the Port of Miami and Port Everglades, booking cutoffs for DG cargo come earlier than for general freight, so documentation needs to be right the first time. Our mobile hazmat documentation team prepares DG declarations on site in Miami-Dade and Broward when timing is tight.
Common mistakes that stop Class 3 freight
The mistakes we see most often: classifying from a marketing data sheet instead of the SDS; shipping PG II product in packaging only rated for PG III; missing orientation arrows; describing “paint” as UN1993 instead of UN1263; and tendering air shipments with a ground-only limited quantity mark. Any one of these can strand a shipment on the dock and trigger reinspection fees.
A short training cycle fixes most of them. DOT requires hazmat employee training every three years, and Go Hazmat’s training courses cover Class 3 classification, packaging, and documentation for ground, air, and ocean crews.
Shipping Class 3 from South Florida
Miami is a natural gateway for coatings, solvents, and fuel additives heading to Latin America and the Caribbean. Go Hazmat operates hazmat-rated warehousing minutes from Miami International Airport and the seaports, with certified staff who can classify, repack, document, and tender Class 3 freight by any mode. Request a quote through our contact page and a DG specialist will scope your shipment the same day.
Frequently asked questions
What flash point makes a liquid a Class 3 flammable liquid?
A liquid with a flash point at or below 60 °C (140 °F) is regulated as a Class 3 flammable liquid under DOT, IATA, and IMDG rules. The flash point comes from Section 9 of the product’s SDS.
Can I ship paint as a limited quantity?
Often yes by ground, if each inner packaging is 5 L or less for PG II or PG III paint and the package carries the limited quantity mark. Air shipments follow different, stricter limits under IATA, and some entries lose the relief entirely.
Do I need placards for Class 3 freight?
By ground, placards are generally required when you tender 1,001 lbs or more aggregate gross weight of Class 3 in non-bulk packages, and always for bulk packagings. Your carrier must be given placards or placarded freight as required.
