What is the test for whether a statute prohibits the wilful violation of an occupational safety order is unconstitutional?

Defendant contends that the statute prohibiting the willful violation of an occupational safety order ( 6425, subd. (a) ) violates the due process clause of the United States Constitution because it does not provide adequate notice of what conduct is prohibited and allows for arbitrary and discriminatory enforcement. We review de novo the question of whether a statute is unconstitutional. ( Sanchez v. State of California (2009) 179 Cal.App.4th 467, 486, 101 Cal.Rptr.3d 670.)

A penal statute will be upheld against a facial vagueness challenge so long as it warns of what conduct is prohibited with a reasonable degree of certainty, as measured by common understanding and experience. ( People v. Ellison (1998) 68 Cal.App.4th 203, 208, 80 Cal.Rptr.2d 120.) Defendant asserts the statute is vague because it does not provide sufficient warning that supervisory employees, in addition to employers, may be prosecuted for willful violations of safety regulations. Defendant does not maintain that the language of the statute itself is vague; rather, his argument is that a person reading only the text of the underlying regulations would not have notice that the statute subjects supervisory employees to criminal liability for violating them.