The U.S. Environmental Protection Agency announced Tuesday that it has reached a settlement worth at least $21.5 million with aerospace supplier Goodrich Corp. that will require the company to clean up a Southern California industrial site where chemicals contaminated the water supply.

The settlement ends nine years of litigation over the 160-acre B.F. Goodrich Superfund Site in Rialto, which was used for decades by defense contractors and fireworks manufacturers, the EPA said in a statement. Goodrich used it from 1957 to 1962 to develop rocket fuel.

Under the settlement, Goodrich will install new wells for monitoring and testing groundwater at its own expense, then build and operate cleanup facilities with EPA oversight until the process is finished, which could take decades.

Goodrich will pay at least the first $21.5 million toward the cleanup, with contributions also coming from the Department of Defense and several companies that used the site to manufacture fireworks, fuel and munitions and were part of 2012 settlements, the statement said.

Similar sites have cost more than $40 million to clean up, and total costs could reach $100 million, the EPA said.

The cities of Rialto and Colton and San Bernardino County, which sued Goodrich in 2004, were also parties to the settlement.

Phone and email messages left after business hours for a Goodrich spokesman were not immediately returned.