The decades-long effort to eradicate tobacco use in the United States has been among the most important public-health achievements of recent times, saving countless lives and improving countless more. But even as national attitudes about smoking have changed, tobacco use has remained deeply ingrained in significant elements of the culture.

One big-league example: professional sports, particularly baseball, in which the disgusting and deadly smokeless tobacco habit continues to claim many addicts.

Major League Baseball owners have tried to get players to cut out smokeless tobacco products, such as chew, dip and snuff, for years, with limited success. Last month they struck a new contract with the players union that aims to phase out smokeless tobacco use, barring new players from dipping. That is progress.

If this were merely an issue of a few pro athletes deciding to expose themselves to deadly carcinogens, it would not be a public-health issue. But sports stars set an example. They are (mostly) known for being in peak physical shape; if they can dip and play pro ball, why not everyone else?

The Centers for Disease Control and Prevention found last year that, though smoking rates are low for high school athletes, use of smokeless tobacco products is high in this group.

Even with the new contract, it may take a while for the culture to change. Smokeless tobacco has been banned in the minor leagues and by the NCAA for years, yet telltale wads still show up in players’ mouths. Moreover, current MLB players will still be allowed to use, meaning it would take well over a decade for everyone in the major leagues to be covered.

The contract will run for five years, so the policy cannot be strengthened for a while. Then there is the question of how well teams and league officials will enforce the ban.

MLB organizations should keep the pressure on, reminding players that tobacco use of all kinds has consequences. San Diego Padres great Tony Gwynn tragically died of salivary gland cancer complications at the age of 54. Pitching legend Curt Schilling waged a fight against oral cancer not long after retiring from baseball.

Cities can take an even harder approach — 12 of them have banned smokeless tobacco from professional sports stadiums within their limits. More should follow suit.

The fight against tobacco cannot stop with smoking. In all its uses, this addictive weed still constitutes a public-health disaster.

The sooner major league sports make smokeless tobacco a memory of an earlier, less informed era, the better.

Editorial by The Washington Post