Kia is recalling about 320,000 cars in the U.S. to fix a problem that could prevent the trunk from being opened from the inside.

The recall covers the Optima midsize car from 2016 through 2018, Optima hybrids and plug-ins from 2017 and 2018, and the Rio small car from 2016 and 2017.

Kia says in documents posted Thursday by U.S. safety regulators that the trunk latch base can crack, and may not open from the inside. The National Highway Traffic Safety Administration says a person inside the trunk could become trapped.

Dealers will replace part of the trunk latch base. Owners will be notified by letter starting Oct. 19.