For former professional pitcher Curt Schilling, the lesson of smokeless tobacco was learned too late. Schilling announced last week that he was treated for squamous-cell carcinoma in his mouth, and he attributes the cause to smokeless tobacco products he used throughout his professional playing career.

The dangers of smokeless tobacco and the prevalence among professional baseball players have long been recognized. Back in 1992, members of the Massachusetts Department of Public published a review paper in the American Public Health Association's national journal encouraging the public campaign against smokeless tobacco products.

"Use of oral snuff has risen sharply among baseball players following a tobacco industry marketing campaign that linked smokeless tobacco with athletic performance and virility," the introduction to the paper stated. "Millions of adolescents have copied these professional role models and, today, are at risk of developing oral cancer and other mouth disorders. New policies and programs are needed to break the powerful grip that the tobacco industry has on professional sport."

The leaves from the tobacco plant can be smoked, chewed and sniffed. The addictive ingredient is nicotine, but tobacco contains at least 19 chemicals known to cause cancers. Furthermore, nicotine has been implicated in increased cardiovascular risk in healthy athletes.

Regardless of the mode of intake, tobacco use has significant health risks. The addition to nicotine is strong and is the most common form of addiction in the United States. Studies are finding that nicotine may be as addictive as heroin, cocaine or alcohol.

Despite the detriments to health, athletes continue to use nicotine products at a high rate. The use is not confined to baseball. The estimates for active use of nicotine are from 19 to 56 percent percent, and the sports identified as having athletes using nicotine include ice hockey, skiing, biathlon, bobsleigh, skating, football, basketball, volleyball, rugby, soccer, wrestling and gymnastics.

The reason may be that the products contribute to enhanced performance. How this occurs is unclear, and the nature and extent of performance change is controversial, but research indicates potential improvement in visuospatial processing, alertness and orienting, motion, force energy and endurance. The improvements are such that it has been suggested that nicotine be added to the official list of banned drugs in athletes.

The culture of tolerance and glamour surrounding tobacco products is taking its toll on America's youth. The Centers for Disease Control and Prevention reported that 6.7 percent of middle school and 23.3 percent of high school students used tobacco products in 2012. And 11 percent of high school males use smokeless tobacco products similar to those that caused cancer in Schilling.

Some players learned the lesson of harm from smokeless tobacco the hard way and are sharing. Former San Diego Padres star and 2007 inductee into the Baseball Hall of Fame Tony Gwynn was forthcoming about his diagnosis of salivary gland cancer and his addiction to smokeless tobacco.

Gwynn and his family hoped that others will learn from his painful experience. Gwynn began using early in his career and dipped smokeless tobacco at his house, his locker and on the field with a habit of a can and half every day. Gwynn died June 16 at age 54.

Recognizing the responsibility organized baseball plays as role model for young athletes, minor league baseball banned the use of smokeless tobacco products in 1993. Two United States legislators proposed the same for Major League Baseball shortly before the start of the 2011 World Series.

Rep. Henry Waxman (D-Calif.) and Frank Pallone (D-N.J.) requested a ban on smokeless tobacco products in a letter the baseball commissioner Bud Selig and the executive director of the players' union. They had the support for the efforts to curtail the use of smokeless tobacco products from several organizations including The Campaign for Tobacco-Free Kids, the American Academy of Pediatrics, the American Cancer Society and the American Medical Association.

"These issues affect the integrity of the game, the health of your players, and most important, the health of teenagers who aspire to be like pro players," both legislators commented.

Perhaps the stories of Schilling and Gwynn will make Major League Baseball more attentive this year.