Del. Code tit. 7, § 7409A

The Department shall promulgate regulations containing requirements for maintaining evidence of financial responsibility as deemed necessary and desirable for taking reasonable corrective action for property damage and bodily injury caused by accidental release arising from operating an aboveground storage tank. Evidence of financial responsibility may include, but not be limited to, insurance, guarantee, surety bond, letter of credit, proof of assets, or qualification as a self-insurer. In promulgating regulations under this section, the Department is authorized to specify policy or other contractual terms, conditions or defenses which are necessary or are unacceptable in establishing evidence of financial responsibility in order to effectuate the purposes of this section.