Pornography will have to come with a warning label in Utah after Gov. Gary Herbert allowed the measure to become law over protest from the adult-entertainment industry.

If producers don't include a one-sentence warning label on obscene materials about potential harm to minors, they could face a $2,500 penalty per violation. Herbert allowed the measure to become law without his signature on Wednesday.

The measure is aimed at helping people worried about the widespread availability of porn online, Republican sponsor Rep. Brady Brammer has said.

After criticism that the measure could be unconstitutional, it was aimed at porn deemed to be legally obscene. Most porn doesn't qualify, but hardcore material declared obscene doesn't have constitutional protections.

The Free Speech Coalition, an adult-entertainment trade group, has said the law could still unfairly force porn producers to defend themselves in court because it allows private citizens as well as the state to file complaints.

A judge would have to decide if the porn qualifies as obscene. Producers could avoid the penalty by showing that they have included the label most of the time.