The FDA has a warning for Horizon Air: If there’s no hand-washing, don’t serve ice.

According to The Seattle Times, the FDA sent a letter to Horizon Air, operating by Alaska Airlines, reprimanding employees for serving ice with drinks on their Bombardier Q400 airplanes, which don’t have hand-washing sinks in their bathrooms.

Without hand-washing facilities, the lavatories aren’t sufficient for employees to handle food and ice, which “can increase the potential spread of communicable disease,” said the letter.

The letter comes after several FDA inspections last winter, which led to correspondence with Horizon on the issue for months. The Times reports Horizon fixed other problems noted in the inspections, but employees continued to serve drinks with ice.

“Directing your employees to wash their hands in the airport between flights or to use hand sanitizer does not meet the requirements for suitable lavatory facilities for food-handling employees. We recommend that you discontinue the use of ice and serve only food and beverages that are in closed containers,” the FDA wrote to Horizon.