Cool Runnings

Derice Bannock, a top 100m runner, fails to qualify at the Olympic Trial for the 1988 Summer Olympics when fellow runner Junior Bevil trips and falls, taking Derice and another runner, Yul Brenner, with him.
To compete in the Olympics, he and his best friend, Sanka Coffie, a champion push cart racer, seek out Irv Blitzer, an old friend of Derice's father Ben who tried to recruit sprinters to the bobsled team years ago. Irving is an American bobsled two time Gold Medalist at the 1968 Winter Olympics who finished first in two events again during the 1972 Winter Olympics but was disqualified from the latter for cheating and retired in disgrace to Jamaica, where he leads an impoverished life as a bookie. Derice's persistence eventually convinces Irving to be their coach and return to the life he left behind. They eventually recruit Junior and Yul, though Yul is still upset over Junior's mistake at the Olympic Trial.
The four try to find various ways to earn money to get in the Olympics but no sponsor takes the idea seriously and their various enterprises, from singing on the street to arm wrestling, and holding a kissing booth, all fail. Junior comes through for them when he sells his car, which gets the team the money that they need. Later on in a hotel room, Junior reprimands Sanka for hurting Yul's feelings over his ambitions. Junior tells the team about his own father's struggle and how he became rich with hard work. He encourages Yul not to give up on achieving all of his goals and the two begin to show a mutual respect for one another.
In Calgary, Irving manages to acquire an old practice sled, as the Jamaicans have never been in an actual bobsled. The Jamaicans are looked down upon by other countries, in particular the East German team whose arrogant leader, Josef, tells them to go home, resulting in a bar fight. At the hotel room, Derice and Irv reprimand Sanka, Yul and Junior and remind them what is at stake for the team. The team resolves to view the contest more seriously, continuing to train and improve their technique. They qualify for the finals, but are subsequently disqualified due to a technicality which the Olympic committee trotted out as retribution for Irving's prior cheating scandal. A frustrated Irving storms the committee meeting and confronts his former coach from the 1972 Olympic Winter Games Kurt Hemphill, now a primary judge of the 1988 Olympic Winter Games. He takes responsibility for embarrassing his country with the scandal and implores the committee just punish him for his mistake, not the Jamaican team. Irv reminds them that the Jamaicans deserve to represent their country by competing in the Winter Games as contenders. That night at their hotel, the team gets a phone call informing them that the committee has reversed its decision and allows the Jamaicans to once again compete.
The Jamaicans' first day on the track results in more embarrassment and a last place finish. Sanka identifies the problem as Derice trying to copy the Swiss team which he idolizes and convinces him that the best they can do is bobsled Jamaican. Once the team develops their own style and tradition, the second day improves; the Jamaican team finishes with a fast time which puts them in eighth position. Derice asks Irving about why he decided to cheat despite his gold medals and prestige; Irving tells Derice, "A gold medal is a wonderful thing, but if you're not enough without it, you'll never be enough with it," and convinces him to think of himself as a champion even if he fails to win the gold.
For the first half of the final day's race it looks as though the team will break the world bobsled speed record, until tragedy strikes: due to the sled being old, it cannot handle the high speed and eventually one of the sled's blades comes loose, causing it to flip onto its side as it comes out of a turn, leaving the team meters short of the finish line. Determined to finish the race, the team lift the sled over their shoulders and walk across the finish line to rousing applause from spectators, including Josef, Hempill, and Junior's father. The team, at the end, feel accomplished enough to return in four years to the next winter Olympics. A brief epilogue states the team returned to Jamaica as heroes and upon their return to the Winter Olympics four years later, they were treated as equals.

Question: Why was Irv disqualified from the 1972 Olympics?
Answer: For cheating