cavelamb himself wrote:

:I'm kind of confused about that...

:WHY would a vengted can be illegal?

They're a substantial source of air polution. Really. Spilling an
ounce of gasoline while filling your lawnmower generates as much
unburned hydrocarbons as burning the fuel in the tank mowing the lawn.
Unburned hydrocarbons are a major contributor to smog.