Seventy-five former players sued the National Football League, claiming it concealed information about the danger of concussions for decades.
Raymond Clayborn, Ottis Anderson and Mark Anderson are among the plaintiffs in the negligence, fraud and liability suit that was filed Tuesday in Los Angeles Superior Court. Many players' wives also are plaintiffs.
The suit alleges the NFL knew as early as the 1920s of the harmful effects of concussions but concealed them from coaches, trainers, players and the public until June 2010. It also names Riddell, the NFL's official helmet supplier.
It seeks unspecified damages.
"We have not seen the complaint but would vigorously contest any claims of this kind," NFL spokesman Greg Aiello said in a statement.
A statement from Riddell was being completed, spokesman Jack Yeo said.
Concussions are movements of the brain inside the skull from an impact. The former players contend that they suffered repeated concussions from hits and tackles during their years in the NFL that caused brain damage. They contend the injuries left them with problems such as dementia, headaches, memory loss, blurred vision, sleeplessness and ringing in the ears. Some claim the injuries caused depression, anxiety, "explosive mood changes," poor judgment and substance abuse.
According to the suit, the NFL knew for decades that multiple blows to the head can cause long-term brain injury but fraudulently denied it, even as independent evidence showed that players were at risk.
The Mild Traumatic Brain Injury Committee was established by the NFL in 1994 to study the risk of long-term brain injury to players. The suit contends the committee published "false, distorted and deceiving" findings that the risk was minimal in order to deceive Congress, players and the public.
The NFL only warned active players in June 2010 of the risks associated with multiple concussions and Riddell failed to warn active players until around the same time, the suit claims.
The NFL has never warned past players, according to the suit.