The warnings always say (at least)
DANGER GASOLINE
EXTREMELY FLAMMABLE VAPORS CAN EXPLODE
HARMFUL OR FATAL IF SWALLOWED
If swallowed, do not induce vomiting, call physician immediately
Keep out of reach of children
Avoid prolonged breathing of vapors Do not siphon by mouth
Do not store in vehicle or living space. Store and use in well-ventilated area
Vapors can be ignited by a spark or flame source many feet away
Keep away from flame, pilot lights, stoves, heaters, electric motors, and other sources of ignition
Keep container closed
Portable Fuel Containers are designed to mitigate some of these hazards:
• by including features to minimize vapor emissions and spills
• by having Child Resistant closures
• by having flame mitigation devices in each opening
But safety depends on responsible and safe use of gasoline by the consumer.
GASOLINE VAPOR
Designed to power spark ignition engines, gasoline has a very low flash point (the lowest temperature at which its vapor will ignite, if given an ignition source) and produces significant vapor at normal temperatures. Gasoline vapors are highly explosive and exposure to ignition sources must be avoided when filling a container or pouring into a fuel tank.
NEVER USE GAS TO START OR ACCELERATE A FIRE