It's a civil infraction, like a speeding ticket or a heavy equipment rebuilder that makes the mistake of painting a bunch of stuff with paint that doesn't meat whatever this years EPA VOC rules are.
If you're not rich enough to lawyer up, spend five figures fighting through the kangaroo administrative process and then another five sticking it to them in real court a civil infraction is actually worse in a lot of ways because those pesky 4th through 8th amendments don't really protect you all that much. There's a lot of judicial precedent from the past 100yr that basically waters down your rights when a bureaucrat is after you rather than the cops.
So it is still illegal, right?