COLUMBUS, Ohio -- The NFL hasn't done enough to protect its players from potential injuries or deaths caused by heat-related illnesses, says a lawsuit filed by the widow of former Minnesota Viking Korey Stringer.

Kelci Stringer sued the NFL in U.S. District Court on Monday, filing a suit that says the league fosters a "deadly culture" of abusive exercise that contributed to the death of the Minnesota Vikings' lineman during training camp in 2001.

The suit seeks unspecified financial damages and asks the court to stop the NFL from forcing players to practice and play in high heat and humidity. It says NFL coaches, trainers and doctors subject players to potentially fatal conditions by forcing them to participate in practices while wearing improper clothing for such conditions.

The lawsuit also says NFL helmets and shoulder pads provided by Riddell Inc. of Chicago unnecessarily insulate players in hot temperatures, preventing evaporation and increasing the risk of heat-related illness.

"A perverse, insidious and deadly culture has existed and continues to exist among NFL coaches, which unreasonably subjects players to heat-related illness during practices, ostensibly out of the twisted belief that players benefit from being subjected to such working conditions," the lawsuit says.

Stringer, a 335-pound Pro Bowl lineman who played at Ohio State, collapsed July 31, 2001. His body temperature was 108.8 degrees when he arrived at a hospital. He died 15 hours later.

The lawsuit's goal is to change "the practices and culture of the NFL, so that what was a completely preventable death never occurs in the NFL again," said James Gould, Stringer's agent.

The lawsuit names the NFL, Riddell, and Dr. John Lombardo, a Columbus sports physician who the lawsuit says is a member of the NFL safety and injury panel and advises the NFL on health issues. Lombardo is also the head of the NFL's drug program.

The lawsuit is seeking class-action status on behalf of NFL players, their wives and families.

"We have not seen the lawsuit and cannot comment on the substance of it. We share the Stringer family's sadness, but we are surprised and disappointed that the approach to this tragedy is to continue to pursue a strategy of litigation," NFL spokesman Greg Aiello said.

Messages were left with Lombardo and Riddell.

Stringer earlier sued the Vikings and the team's training camp doctor, David Knowles. A Minnesota judge dismissed her claims against the team and she later settled with Knowles for an undisclosed sum.

The league has said it already made changes after Korey Stringer's death.

Before training camp opened in 2002, the NFL consulted with several experts and held a series of discussions and seminars on the subject. The league banned the herbal stimulant ephedra and began random testing for it last summer after learning that dietary supplements increased the risk of heat-related illnesses.

A bottle of Ripped Fuel, which contains ephedra, was found in Stringer's locker after he died, though Stringer's remains weren't tested for the substance during investigations of his death.