TAMPA — Pinellas school superintendent Mike Grego stood before state educators this week with a simple message: You can't spend money you don't have.But that's precisely what Florida school districts are being asked to do, he says. Without providing additional money to school boards, the Legislature this year enacted a law requiring public schools to pay the bill for high school students who take college classes for free. Previously, colleges absorbed most of those costs.The unexpected change to the dual enrollment program will cost Florida school districts as much as $60 million this year, said Grego, speaking for the Florida Association of District School Superintendents. The cost could even cause some districts to stop providing a dual enrollment option — an increasingly popular way for high school students to get a head start on college.Education Commissioner Tony Bennett recommended that schools deal with the new costs by looking at Advanced Placement classes or College-Level Examination Program tests as ways of accelerating students instead of dual enrollment.In the long term, school leaders plan to lobby legislators to change the law. In the short term, many school districts and college leaders are working to find compromises to keep the program vibrant in the face of the surprise legislation."It's an unfunded mandate," Grego said.He estimated the added cost for dual enrollment would come to about $1.7 million in Pinellas, though the district was able to reach an agreement with St. Petersburg College to offset that amount. Hillsborough estimates the cost around $1.1 million. Pasco County school officials predicted a cost of about $500,000, while their counterparts in Hernando County said costs could be up to $400,000."There's no question that it's a burden," said Hernando superintendent Bryan Blavatt. "We really haven't had time to prepare for it."Passed at the end of the legislative session, the new law follows enormous growth in the number of students taking dual enrollment. More than 50,000 participated across the state in 2011-2012, the most recent school year for which numbers were available. That's expected to grow.State Board of Education Board member Kathleen Shanahan blamed college presidents for orchestrating an effort to push the change through the Florida Legislature."It's very disappointing that they did this in a secret fashion," she said at a meeting this week to a group that included a smattering of superintendents. "You guys got out-lobbied. And we didn't know anything about that. And I think that's disrespectful."She said the change in law put the State Board of Education in an uncomfortable position because it manages both the colleges and K-12 education system."If it's a $60 million impact on the pre-K through 12 system," Shanahan said, "we should have known about that."But St. Petersburg College president Bill Law said state colleges never intended to transfer dual enrollment costs to local school districts. Instead, he and other college presidents wanted to explore using Bright Futures dollars to pay for students' classes to offset growing costs."It's a mess," Law said. "I don't know that anyone started to do wrong here. But, boy, we wake up here and there are some hurt feelings across the state."Law said dual enrollment students may have been an easy target because they're a growing group and one that doesn't pay tuition. More than 2,900 students are dual-enrolled at SPC, an all-time high.Law and Grego know they have to comply with the law, but they're looking for ways to keep Pinellas schools from having to actually pay up. One way: The district could start charging SPC rent when it uses local schools to teach classes, effectively canceling out the $1.7 million bill."There's a lot of ways to make this work," Law said.Dual enrollment in recent years has taken a toll on colleges, which foot most of the bill.Consider Pasco-Hernando Community College. Since 2009, enrollment in the program jumped 34 percent. The associated costs, including registration, tuition and laboratory fee waivers, have gone up 57.5 percent, surpassing $2.5 million.At a meeting in February with local school representatives, officials with the college gave the program a familiar name. Just like the school district superintendents, they called it an unfunded mandate.Times staff writer Jeffrey S. Solochek contributed to this report.