Ford Motor Co. is recalling 33,021 C-Max hybrid cars because they may not adequately protect occupants’ heads in a crash.

Vehicles involved were made between Jan. 19, 2012, and June 25, 2013 and don’t have panoramic roofs. C-Max hybrids with panoramic glass roofs aren’t involved in the recall.

The National Highway Traffic Safety Administration discovered during vehicle testing that the car failed to conform to safety standards pertaining to head injury risk. Ford says there have been no reported injuries related to the issue.

Ford will notify owners of the recall next month. Dealers will install additional energy absorbing material between the car’s headliner and the roof.

Owners may also contact the National Highway Traffic Safety Administration Vehicle Safety Hotline at 1-888-327-4236 (TTY 1-800-424-9153), or go to www.safercar.gov.