Greenberg, J.
This appeal arises from the allowance of a motion for summary judgment on a complaint for contribution. The plaintiffs, formerly trustees of a real estate trust which owned a textile mill in Newton (trustees), were sued in 1989 by the general partners of a development company (developers) who had purchased the property from the trustees in 1985. When the developers discovered that number six fuel oil had escaped from an old underground tank located on the property, they brought a civil action against the trustees pursuant to G. L. c. 21E, §§ 4 & 5, and G. L. c. 93A, § 11 (underlying action). Royal Insurance Company of America (Royal) and four other *245insurers disclaimed coverage for damages claimed against the trustees; only Wausau Underwriters Insurance Company (Wausau) agreed, under a reservation of rights, to advance the trustees their legal fees and expenses in defending the underlying action. As a result, the trustees brought an action under G. L. c. 231A for a judgment declaring that the developers’ claims were within the scope of the policies issued by Royal and the four other insurers. In June, 1991, the trustees agreed to settle the underlying action by paying to the developers $425,000. By that time, Wausau had paid $261,902.84 in legal fees and expenses in defending the trustees. The trustees continued to pursue the declaratory judgment action, which became primarily an action for damages in which they sought to recover the $425,000 paid to settle the underlying action. On October 12, 1994, a Superior Court judge ruled that Royal had a duty to defend them and was' obligated to reimburse them for the reasonable costs of defending that action.2 We affirmed the judgment in that case. See Rubenstein v. Royal Ins. Co., 44 Mass. App. Ct. 842 (1998).