More than 500,000 child car seats made by a company called Diono are being recalled because they may not adequately protect children in a crash.

The recall covers the Radian R100, Radian R120, Radian RXT, Olympia, Pacifica, and Rainier convertible and booster seats. They were made from as early as January of 2014 to September of this year by Diono, which used to be called Sunshine Kids Juvenile.

Documents posted Thursday by the U.S. National Highway Traffic Safety Administration say that when the seats are secured using a lap belt without the top tether, children over 65 pounds have an increased risk of chest injury in a crash.

Diono, based in Sumner, Washington, says it has no reports of injuries and that few children who weigh more than 65 pounds will harnessed into the seats. The problem was discovered in company testing.

The company will send owners a kit with an energy absorbing pad and a new chest clip at no cost. The recall is expected to start Nov. 22.

Customers with questions can call Diono at (855) 463-4666.