This website contains age-restricted materials including nudity and explicit depictions of sexual activity.
By entering, you affirm that you are at least 18 years of age or the age of majority in the jurisdiction you are accessing the website from and you consent to viewing sexually explicit content.
Maybe they got the 4 part mixed up from the old chem rhyme:
Johnny was a chemist, but Johnny is no more, because what he thought was H2O was H2SO4