Coastal Petroleum Company (Coastal) and other interested persons appeal a final order of the Department of Environmental Protection (department) denying Coastal’s application for a permit to drill for oil and gas. The department denied the permit on the ground that it had not been notified by the Board of Trustees of the Internal Improvement Trust Fund (the trustees) that it had received financial security in the amount of $1.9 billion being required by the trustees. Coastal argues on appeal that the department had no legal basis to deny its application for a drilling permit because the trustees lacked the authority to impose the $1.9 billion bond requirement. We agree and reverse on the authority of Coastal Petroleum Co. v. Chiles, 672 So.2d 571 (Fla. 1st DCA 1996), in which this court held that the trustees’ retroactive application of section 253.571, Florida Statutes, to a preexisting oil and gas lease to impose a $1.9 billion bond requirement impaired obligations under Coastal’s lease contract and thereby contravened Article I, section 10 of the state constitution.

REVERSED and REMANDED.