Powders & Granular Items Checker
Under security rules introduced in 2018, powder-like substances over 12 oz (350 ml / roughly the size of a standard soda can) trigger mandatory secondary screening and chemical swabs.
Why Security Screeners Inspect Large Powders
1. The Radiographic Density Match (Effective Atomic Number Z_eff)
Finely milled organic powders have effective atomic numbers (Z_eff) and X-ray absorption signatures identical to plastic and sheet explosives (such as RDX and PETN). When large tubs of powder pass through standard checkpoint X-ray scanners, automated detection algorithms automatically flag them as suspicious high-density anomalies.
2. The Separate Bin Protocol
If you choose to carry powders exceeding 350 ml in your carry-on bag, remove the container from your luggage and place it in a separate bin—just like a laptop. This keeps your main bag from failing the initial scan and avoids complete unpacking.
3. Checked Bags Have No Powder Limits
The 350 ml (12 oz) limitation applies exclusively to cabin carry-on baggage. You can pack 5 lb (2.2 kg) tubs of protein powder, creatine, or baking supplies in your checked suitcase without triggering checkpoint secondary screening.