The GHS flame pictogram on a chemical label tells you the product can ignite — but it doesn't tell you how easily. A flammable aerosol and a pyrophoric compound both carry the flame symbol, but their hazard levels are vastly different. Understanding what the flame symbol means and what to do about it is the first step in preventing construction site fires from chemical storage and use.

• Flammable gases: LPG, propane, acetylene — ignite easily at room temperature in air
• Flammable aerosols: Spray paints, adhesives, penetrating oils — pressurized flammables in a fine mist that ignites even from a hot surface
• Flammable liquids (Categories 1–3): Flashpoint below 140°F — includes gasoline, acetone, lacquer thinner, mineral spirits
• Flammable solids: Some cutting wires, metal powders — can ignite from friction or heat
• Self-heating substances: Certain oily rags, some metal powders — can ignite spontaneously if improperly stored (oily rag fires are common in NYC)

• No smoking or open flames within 35 feet of storage or use area
• Eliminate ignition sources: power tools, grinders, and cutting equipment create sparks that can ignite flammable vapors
• Flammable vapors are heavier than air — they travel along the floor to distant ignition sources. Ventilate from low points
• Oily rags: place in a self-closing, UL-listed oily waste can at end of each shift — never pile them or leave in an enclosed space overnight