Wal-Mart (WMT) must pay at least $78 million for violating Pennsylvania state labor laws by forcing employees to work through rest breaks and off the clock, a jury decided Friday.

Michael Donovan, a lawyer for the plaintiffs, had asked the jury for at least that amount for what he said were missed or shortened breaks, or time employees worked off the clock.

The class-action suit involves 187,000 current and former employees who worked at Wal-Mart and Sam's Clubs in Pennsylvania from March 1998 through May of this year. The Common Pleas Court jury found Thursday that the retail giant violated state labor laws.

Lead plaintiff Dolores Hummel, who worked at a Sam's Club in Reading from 1992-2002, charged in her suit that she had to work through breaks and after quitting time to meet work demands in the bakery. She said she worked eight to 12 unpaid hours a month, on average, to meet work demands.

"One of Wal-Mart's undisclosed secrets for its profitability is its creation and implementation of a system that encourages off-the-clock work for its hourly employees ..." Hummel said in her suit, which was filed in 2002.

The plaintiffs used electronic evidence, such as systems that show when employees are signed on to cash registers and other machines, to help win class certification during several days of hearings last year.

Wal-Mart had a corporate policy that gives hourly employees in Pennsylvania one paid 15-minute break during a shift of at least three hours and two such breaks, plus an unpaid 30-minute meal break, on a shift of at least six hours.