Twenty-two Teamsters drivers for SuperMom's bakery in St. Paul Park have been locked out of their jobs in a contract dispute. While a small work stoppage, it's part of growing national wave of labor lockouts initiated by corporations.

SuperMom's supplies doughnuts and other food to area SuperAmerica stores. Both the bakery and the gas and convenience outlets are owned by Connecticut-based Northern Tier Energy.

Drivers were handed a notice Friday -- some while loading their trucks -- saying "leave the property," said Brad Slawson Jr., president of Teamsters Local 120. They were told not to return until further notice.

The lockout came after the Teamsters rejected the company's final contract offer and authorized a strike, said Northern Tier spokeswoman Christine Carnicelli.

Teamsters Local 120's contract at the bakery expired Aug. 9. Negotiations were beached over management's demands for wage freezes and overtime concessions, Slawson said. Local 120, one of the Twin Cities' oldest Teamsters locals and the cities' primary drivers local, hasn't experienced a lockout in at least 50 years, Slawson said.

Carnicelli said the company surveyed its local competition and found that SuperMom's drivers are being paid 25 percent above the market rate. "Delivery costs are a significant cost to the business," she said.

Top pay for SuperMom's drivers is about $20 per hour. That is among the lowest pay rates for "Class B" drivers in the several hundred contracts administered by Local 120, Slawson said. Plus, Northern Tier's SuperAmerica operations are amply profitable, he said.

Northern Tier bought SuperAmerica's 200-plus Minnesota stores and its St. Paul Park refinery in October 2010 from Marathon Oil, a $900 million deal.

According to Bloomberg BNA's website, lockouts as a percentage of all U.S. work stoppages in 2010-2011 -- 9.64 percent -- were up sharply over the past two decades. That percentage averaged 5.48 percent between 2000 and 2009 and 4.07 percent during the 1990s.

One of the largest recent lockouts involves Moorhead-based American Crystal Sugar, which locked out 1,300 workers Aug. 1, 2011, after they rejected a contract.

Mike Hughlett • 612-673-7003