(Reuters) - DuPont and Chemours Co have agreed to pay $671 million in cash to settle thousands of lawsuits involving a leak of a toxic chemical used to make Teflon, the companies said on Monday.

FILE PHOTO -- The Dupont logo is displayed on a board above the floor of the New York Stock Exchange shortly after the opening bell in New York, U.S. on December 22, 2015. REUTERS/Lucas Jackson/File Photo

Shares of Chemours jumped 13 percent. The company said it would pay half of the settlement, although liability for litigation connected with the chemical was passed onto it when DuPont spun it off in 2015.

In addition, Jefferies analyst Alexander Laurence said the liability was $300 million below Wall Street estimates, and DuPont shares rose 1 percent.

The companies settled about 3,550 personal injury claims arising from the leak of perfluorooctanoic acid, which is also known as PFOA or C-8, from its plant in Parkersburg, West Virginia.

The leak allegedly contaminated local water supplies and has been linked to six diseases, including testicular and kidney cancers.

“We look forward to working with DuPont to finalize this settlement and get these injured class members paid as quickly as possible,” plaintiffs’ lawyer Rob Bilott said in a statement.

Both companies denied any wrongdoing.

DuPont said in a statement that it had stopped using C-8 in operations at the West Virginia plant more than a decade ago. It had used the chemical there since the early 1950s.

Chemours General Counsel David Shelton called the settlement a “sound resolution.”

The settlement comes as DuPont and Dow Chemical Co expect to close their $130 billion merger later this year.

In 2001, residents brought a class action against DuPont over C-8 exposure. The company agreed in 2004 to fund medical monitoring programs and install new water treatment systems.

DuPont convened a panel of scientists to determine whether any diseases were linked to C-8. The panel concluded that there was a probable link with six illnesses: kidney and testicular cancer, ulcerative colitis, thyroid disease, pregnancy-induced hypertension and high cholesterol.

Members of the class action lawsuit also sued DuPont individually, and the litigation was consolidated in federal court in Columbus, Ohio. The company agreed not to challenge whether C-8 can cause the diseases.

Three verdicts in the litigation totaled $19.7 million. Most recently, a jury last month ordered DuPont to pay a plaintiff $12.5 million, including $10.5 million in punitive damages.

The case is In re E.I. Du Pont De Nemours and Company C-8 Personal Injury Litigation, U.S. District Court for Southern Ohio, No. 13-2433.