The National College Athletic Association has been sued by two former college football players who claim the organization failed to enforce safety measures to protect them from concussions.

Former University of Central Arkansas wide receiver Derek K. Owens and former Northwestern University offensive lineman Alex Rucks allege the NCAA turned a blind eye to coaches who teach players to use their heads for tackling, failed to establish a system for screening head injuries and shirked its financial obligations to injured student athletes, according to complaint filed in federal court in Chicago on Wednesday.

The lawsuit seeks to represent all ex-student football players who sustained concussions and developed chronic headaches, dizziness and mental or physical problems and incurred doctor bills for the illnesses after college.

The complaint also seeks a court order barring coaching of tackling methods that can cause head injuries and establishing a policy for when players can return to play after a head injury. It also asks for a program to medically monitor ex-players and unspecified damages.

Chris Radford, a spokesman for the Indianapolis-based NCAA, didn’t immediately return a voice-mail message seeking comment about the lawsuit. The NCAA “has created several rules designed to prevent the injury, educate student-athletes and coaches, and protect against athletes returning too soon,” the group’s Web site says.