COLUMBIA, S.C. — South Carolina Gov. Mark Sanford on Wednesday vetoed a bill that would have implemented a 15-year replacement cycle for state-owned school buses.

The bill, which was approved overwhelmingly by members of the Legislature, would require the state to purchase 380 new buses each year at a cost of nearly $30 million. South Carolina is the only state to own and operate its school bus fleet. In a letter to House Speaker Robert Harrell Jr., Sanford said the state should consider privatized bus service or leasing a substantial portion of the bus fleet. In the long run, he said, the state should decentralize school transportation services. Sanford's veto still could be overturned by the legislature, which has strongly supported the measure.