Smokers and pro football players have something in common: They engage in risky behavior that can be potentially harmful to their health over time.

And to hear some lawyers tell it, the National Football League is the equivalent of Big Tobacco.

The recent wave of lawsuits filed on behalf of retired players uses similar arguments to those made by attorneys representing smokers who sued tobacco companies more than 15 years ago — in this case, that the National Football League knew repeated concussions could lead to brain damage and yet hid the information.

More than 2,400 retired players are now plaintiffs, looking for the kind of success smokers had against the tobacco companies. The result then was a landmark, $206-billion settlement shared among 46 states. But the ex-players face a huge challenge as they take on a multibillion dollar industry that is the most popular sport in the United States.

"I don't think it's the same good versus evil you saw in the tobacco litigation, but there are some potential similarities," said Gabriel Feldman, director of the sports law program at Tulane University. "It's a lot grayer on both sides. That could change if some smoking guns are found during discovery if the case gets that far."

At issue is whether the NFL knew if there were links between football-related head trauma and permanent brain injuries and failed to take appropriate action. Attorneys for former players such as Jim McMahon and Art Monk accuse the NFL of negligence and intentional misconduct in its response to the headaches, dizziness and dementia that their clients have reported, even after forming the Mild Traumatic Brain Injury Committee to study the issue in 1994. The league has consistently and strongly denied the claims.

"The NFL took a page right out of the tobacco industry playbook and engaged in a campaign of fraud and deception, ignoring the risks of traumatic brain injuries in football and deliberately spreading false information to its players," said Sol Weiss, co-lead counsel for the plaintiffs.

The NFL has said it has spent more than a billion dollars on pension and disability benefits for retired players in a partnership with the NFL Players Association. League officials argue player safety has long been a priority, and it makes health programs available to current and former players, including neurological evaluations.

"Any allegation that the NFL intentionally sought to mislead players or otherwise conceal information from players concerning the risks, treatment or management of concussions is entirely without merit," the league said in a statement.

According to an Associated Press review of 95 lawsuits filed through last Monday, 2,425 players are now plaintiffs in concussion-related complaints against the NFL. The total number of plaintiffs in those cases is 3,762, which includes players, spouses and other relatives or representatives. Some of the plaintiffs are named in more than one complaint, but the AP count does not include duplicated names in the total.

Many of the suits were recently consolidated before a federal judge in Philadelphia, and seek medical care.

League officials have heard the tobacco-concussion comparisons before.

Three years ago, NFL Commissioner Roger Goodell appeared before Congress regarding concussions and didn't acknowledge a connection between head injuries suffered on the field and later brain injuries. Several members of Congress were frustrated with Goodell's testimony, including Rep. Linda Sanchez, D-Calif., who said the NFL's response to the issue reminded her of tobacco companies saying there weren't ill health effects due to smoking but later had to admit there was.

These lawsuits "could have been avoided if the NFL had taken proactive steps to address the issue — pardon the pun — head on rather than obscuring it," Sanchez recently told the AP. "Common decency dictates that the league has a responsibility to these players."

Yet some legal observers said the similarities between the tobacco and concussion lawsuits are superficial at best. Not only does the league have team trainers on the sidelines during games to gauge a player's health but it's difficult to determine what effect a concussion will have, especially if someone has suffered others in the past.

"The allegations deal with what happens after a player is injured — and injuries are expected in football — as opposed to tobacco cases where the initial injury — the smoking-related illness — is the event at issue," said attorney Stephen Brody, who was part of a team of government prosecutors who filed a civil racketeering lawsuit that resulted in a judge finding that tobacco companies conspired to dupe consumers about the health risks of smoking.

"That's where you run into a key difference. On the football field, you have professionals who are taking care of these players and who have access to a growing body of scientific research. In the tobacco cases, the plaintiff already has the injury allegedly caused by the defendant before they see a doctor for treatment."

Up next in the NFL litigation is the league's motion to dismiss the case, which could be filed by Aug. 9. The question there is whether the suits should be thrown out because they are pre-empted under federal labor law by the league's collective bargaining agreement with players. The deal includes the medical care of players, but Bill Gould, a Stanford law professor and former chairman of the National Labor Relations Board, argues retired players aren't part of the agreement.

"The retirees are not employees under the CBA and the National Labor Relations Act," Gould said. "There's no standard set for resolution of these kinds of issues under the CBA."

The NFL has had success with pre-emption before. The Minnesota Supreme Court refused to allow the widow of Vikings lineman Korey Stringer to pursue a wrongful death suit after he died of heatstroke following a 2001 practice. The court found that the claim was pre-empted because its resolution required interpretation of the CBA terms and was inextricably intertwined with federal labor law, Feldman said.

Stringer's wife later settled with the NFL over a negligence claim.

"The league's pre-emption argument has already been accepted by two federal judges in these very litigations, who concluded that plaintiffs' claims were substantially dependent upon and arose under the various collective bargaining agreements under which the plaintiffs' played and therefore preempted by federal labor law," the NFL said.

A judge's ruling on the pre-emption issue is likely to take months, but even if the lawsuits are allowed to move forward, Feldman said it will be difficult to show a direct link between the hits players took in NFL games and the injuries that hamper them now.

"Even if the league knew of these risks, how do these players know whether these injuries were suffered during a game, during practice or even earlier in Pee Wee football or high school or college?" Feldman asked. "There are so many intervening forces to break or at least muddy the (causal) chain."

Most legal experts believe a settlement will have to be considered at some point by the NFL and co-defendant helmet-maker Riddell Inc.

"The financial burden, let alone the bad publicity with protracted litigation, is too much to bear," Gould said.

Said Brody: "One thing you can say given the complexities of the legal issues involved, it's unlikely the litigation is going to be resolved for a long time."