A partial government shutdown is causing some travelers to wait hours in lines for Transportation Security Administration screening as airports experience staff shortages.

Lines at security checkpoints stretched more than an hour at airports across the country Sunday, as the partial government shutdown of the Department of Homeland Security continues.

A statement from Houston Airports, which counts Hobby and George Bush intercontinental airport as part of its system, said the shutdown “can impact security operations day-to-day and shift-to-shift”.