Idaho lawmakers on Friday approved legislation to criminalize the use of bathrooms, locker rooms or changing rooms, even in private businesses, by people whose sex at birth does not match the facilities’ sign on the door.

Senators approved 28-7 what might be the nation’s most restrictive transgender bathroom bill Friday, after the Idaho House approved the ban last week. Gov. Brad Little, a Republican, is expected to sign it.

The legislation makes it a crime for a person of one “biological sex” to “knowingly and willfully” enter bathrooms, locker rooms or changing rooms “designated for the opposite” sex. Violating the law would be a misdemeanor punishable by up to one year in prison. A second offense within five years would be a felony, carrying up to a five-year prison sentence.

Idaho and 20 other states already restrict transgender people from accessing bathrooms, with some laws applying only to elementary and secondary schools and others to all government buildings. Penalties vary — a law enacted earlier this year in Kansas allows private individuals who encounter transgender people using bathrooms that do not match their birth sex to sue for $1,000 in damages.

Idaho’s new law goes farther. It would apply to government buildings and “public accommodations,” including private businesses

During debate in the Idaho House last week, a bill sponsor, State Representative Cornel Rasor, said he proposed the bill at the request of constituents who were concerned about protecting women and girls from “discomfort and voyeurism escalation and assaults.”