Former NFL players sue helmet manufacturer Riddell Inc.

A group of former NFL players, including former Steelers Pro Bowl receiver Yancey Thigpen, have filed a lawsuit against Riddell Inc., saying that the equipment manufacturer did not warn them about long-term health risks that its helmets would not protect them from.

The lawsuit, filed Thursday in Cook County Circuit Court in Chicago, argues that the players suffered personal and financial injuries because Riddell failed to warn them. The players are seeking more than $50,000 in damages and a jury trial.

Thigpen, 46, played 10 years in the NFL from 1991 to 2000, including six with the Steelers. The other players who brought the lawsuit were Gregory Boone, Larry Brinson, Michael Butler, Craig Curry, James Harrell, Willard Harrell, Robert Harris, Carlton "Bailey" Jones, Brad Quast, Thomas "John" Reaves, John Michael Reichenbach, Adam Schreiber and Eric Wright.

The lawsuit was filed one week after Hall of Famer and former Heisman Trophy winner Paul Hornung also sued Riddell, arguing that the helmets did not protect him from brain injury.

Hornung suffered multiple concussions as a running back for the Packers and has been diagnosed with dementia, the lawsuit says. It said that the neurodegenerative disease has been linked to repetitive head trauma.

Concussion lawsuits from athletes have become more common in recent years amid growing awareness about the long-term consequences of repeated blows to the head, and Riddell is also fighting litigation elsewhere. Riddell began producing helmets out of plastic in 1939, touting them as safer alternatives to ones -- more common at the time -- fashioned from leather, according to Hornung's lawsuit.

Riddell has successfully fought some litigation. A Los Angeles jury in 2014 found that Riddell wasn't liable for the severe brain injury of a high school football player who suffered a helmet-to-helmet hit during a game.

Riddell, which provides helmets to every level of football -- from the pros to Pop Warner -- has said publicly previously that it has devoted enormous resources to developing equipment that can reduce the risk of a devastating head injury.

Information from the Associated Press was used in this report.