NEW YORK (Associated Press) - U.S. lawmakers called for a federal review of Florida tomato picker wages and greater oversight of worker conditions during a Senate committee hearing Tuesday, questioning claims by an industry group that the workers earn an average of $12.50 an hour.

Sens. Bernie Sanders, I-Vt.; Edward Kennedy, D-Mass.; and Dick Durbin, D-Ill., expressed concern about the treatment of the Florida workers after the collapse of a plan to get fast-food industry leaders to help boost their wages.

"I want you to do the math with me," Durbin said in his opening statement of the Health, Education, Labor, and Pensions committee hearing.

Workers would have to fill and empty a 32-pound bucket of tomatoes, each worth about 45 cents, about every two minutes all day long to earn the $12.50, he said.

"Is that possible? I don't think it is," he said.

Reggie Brown, head of the Florida Tomato Growers Exchange, testified that his members all treat their workers well and pay them fair wages.

The hearing came months after Burger King and Florida tomato growers joined to overturn the symbolic gains the workers won from fast-food giants McDonald's Corp. and Taco Bell owner Yum Brands Inc. Those companies agreed to pay a penny more per pound of tomatoes in a deal with a local farmworker group. The growers were to pass the money on to their workers.

Advocates hailed the agreement with the Coalition of Immokalee Workers as a first step in boosting wages industrywide. It functioned for two seasons before Florida Tomato Growers Exchange told members it would fine them $100,000 if they participated.

Burger King officials did not immediately return a call seeking comment Tuesday, but they have said they simply don't feel comfortable with the deal.

Brown said legal advisers warned the growers they could be open to antitrust lawsuits and even federal fraud charges if they participated in the deals.

Sanders responded that two top U.S. law firms rejected that view and read from a letter signed by 26 law professors backing the agreement's legality.

"The growers' ostensible concerns over antitrust law are flatly mistaken. The only real antitrust concern would arise if several growers agree among themselves to not participate in the CIW-Yum or CIW-McDonald's monitoring program," the letter stated.

"You might want to reconsider the advice you are getting," Sanders told Brown.

Sanders also recalled several human trafficking arrests made in the southwest Florida town of Immokalee, during his visit there in January and questioned how such incidents could happen under the nose of the industry group.

Brown said such instances were shocking and anomalies.

"Without satisfied workers, no one would pick the tomatoes and we would be out of business," he said. He said growers are competing with cheaper places like Mexico and can't afford to pay more.

Lucas Benitez, co-founder of the worker coalition, said he would be happy if the growers would guarantee $12.50 an hour. He said even if some workers can earn that much or more picking tomatoes, they are paid less or not at all during the hours they wait for the dew to dry or get their tallies checked.

"The vast majority of Americans have no context to understand the work and the conditions that we are in," he said.

Benitez suggested growers offer a surcharge on their tomatoes _ as they have done to offset spikes in oil prices or to ease the cost of phasing out the pesticide methyl bromide _ but with the money going to farmworkers.