What Is a Flammable Gas Label? Definition and U.S. Regulatory Context

Flammable Gas Label A dangerous-goods hazard label used to communicate the transport hazard classification represented by 'Flammable Gas Label'.

Used on packages, overpacks, and transport units, the Flammable Gas Label signals that the package contains a gas which can ignite in air under normal transport conditions. In U.S. domestic transport the label communicates a Division 2.1 hazard (flammable gas) and must match the shipments entry in the hazardous materials table, accompanying shipping papers, and any required placarding on the vehicle.

What The Label Looks Like

The standard flammable gas mark is a diamond-shaped (square on point) label with a white upper half and red lower half, a black flame pictogram, and the word "FLAMMABLE GAS" or the international symbol for flammable gas. It also displays the hazard class number "2" in the lower corner. Size and material must meet regulatory durability and visibility requirements so the label remains legible throughout handling and transport.

Why The Label Matters

First responders, carrier personnel, and handlers use the label to identify risks and apply correct emergency procedures. Warehouse teams rely on it for segregation, storage compatibility, and forklift handling. Carriers use it to determine placarding and routing restrictions; air and vessel operators reference the label to comply with modal dangerous-goods rules. A correct label reduces misrouting, delays, and the risk of improper handling that could cause fire, explosion, or toxic release.

How U.S. Regulations Define And Require It

Federal rules for labeling flammable gases are found in Title 49 of the Code of Federal Regulations (49 CFR). The Hazardous Materials Table in 49 CFR specifies which entries require a flammable gas label (Division 2.1). Specific marking and labeling requirements are covered in the labeling subpart, which sets label design, minimum size, orientation, and placement relative to other marks and handling labels.

How It Varies By Mode

Labeling must follow modal rules in addition to 49 CFR when moving by air, sea, or cross-border. For example, IATAs Dangerous Goods Regulations add placement and quantity limitations for air shipments; the IMDG Code adds stowage and segregation language for sea transport. The graphic and hazard class remain consistent, but the supporting documentation and unit-level controls may differ by mode.

• Label Design: Must match the regulatory design for Division 2.1 with the correct pictogram and class number.
• Durability: Must resist water, abrasion, and fading to remain legible through transport.
• Placement: Applied on a principal panel of the package; not obstructed by straps or shrink wrap.

Common Shipments That Use The Label

Examples include small cylinders of propane (UN 1978), aerosol sprays containing flammable propellants, and industrial gas cylinders with flammable mixtures. Shippers must reference the UN number and proper shipping name to confirm a Division 2.1 classification before labeling.

Practical Steps For Warehouse Teams

Implement a checklist to ensure labels are correct and durable, and that paperwork references the same UN number and class. Integrate label checks into receiving, putaway, and outbound packing checks. Train staff to recognize Division 2.1 labels and the handling rules that apply to those items.

• Verification: Confirm the UN number and proper shipping name on the Bill of Lading or shipping papers match the label.
• Storage: Segregate from oxidizers and heat sources; follow storage limits for quantity and ventilation when storing cylinders.
• Documentation: Keep copies of the Safety Data Sheet (SDS) and shipping papers with the shipment until delivered.

In short, the Flammable Gas Label is the regulated visual cue that a package contains a Division 2.1 flammable gas. Correct label selection, placement, and documentation are required under U.S. transport rules and are essential for safe handling, proper emergency response, and regulatory compliance.