While it has long been illegal to sell alcohol to those younger than 21, Washington state has no laws specifically governing the sale of alcohol at self-checkout machines common in many supermarkets.
With reports reaching lawmakers of self-checkout machines being used by underage buyers of alcohol, the Washington state House on Monday unanimously passed a measure to crack down on the practice.
The bill would require self-checkout machines to freeze transactions involving liquor sales until a worker verifies the age of the buyer.
An earlier version of the bill would have banned outright the sale of alcohol through self-checkout machines.
The measure goes next to the Senate.