The hazmat limit
Updated
On this page8
What the section does
It excepts certain materials from the hazardous materials subchapter when carried by aircraft passengers or crew, provided the incident reporting requirements and the conditions of the section are met. The most appropriate description must be selected and its conditions followed.
The toiletry category
Non-radioactive medicinal and toilet articles for personal use, including aerosols, carried in carry-on and checked baggage. So it covers both, which is the opposite of how people usually think about travel restrictions.
The two numbers
The aggregate quantity carried by each person may not exceed 2 kg by mass or 2 liters by volume, and the capacity of each container may not exceed 0.5 kg by mass or 500 mL by volume. A per-container ceiling and a per-person total.
Capacity, not fill
The limit is on the capacity of each container, so a half-full 750 mL bottle is still a 750 mL container. That is a meaningful distinction for anyone decanting into whatever is to hand.
Aerosols get an extra condition
Release devices on aerosols must be protected by a cap or other suitable means to prevent inadvertent release. A dust cap is doing a regulatory job there, not a cosmetic one.
And one condition about the cabin
The release of gas must not cause extreme annoyance or discomfort to crew members so as to prevent the correct performance of assigned duties. An unusual sentence to find in a hazmat rule, and a clear one.
Every bottle on this shelf is well inside it
The shelf runs 15 to 120 mL across 203 containers, so the 500 mL ceiling is never the constraint here. The constraint is the security limit, which is the next page.