NEW YORK (CNN/Money) - Three dozen insurers led by Travelers Property Casualty Corp. reached agreement Tuesday to settle asbestos-related suits involving PPG Industries Inc. for $2.7 billion.

The agreement is between Travelers, PPG and lawyers for the asbestos claimants. Statements from the companies said the settlement is contingent on a number of significant factors, including the negotiation of a definitive settlement agreement among all the parties in the suits and final court approval. Final approval could stretch more than a year.

Travelers' statement said the insurers would have the option of making a single payment in 2004 or up to 20 annual payments ending in 2023. PPG said it will be taking an after-tax charge of about $500 million to reflect the current value of payments it will make over the 21 years, as well as 1.4 million shares of PPG stock. PPG's 50 percent ownership stake in former asbestos insulation manufacturer Pittsburgh Corning Corp. will also be contributed to the settlement.

Travelers (TAP.A: Research, Estimates) said its proposed contribution under the settlement would be $240 million after tax and discounting. It said it expects payments to be covered by reserves and an indemnification agreement with Citigroup Inc. (C: Research, Estimates), which spun off Travelers through an initial public offering in March.

PPG (PPG: Research, Estimates) and its insurers have been in litigation to determine obligations under policies issued to Pittsburgh Corning, the subsidiary that has been under bankruptcy protection for two years.

"This agreement would enable us to put all our asbestos product claims exposure behind us," said a statement from PPG Chairman Raymond LeBoeuf. "Although we continue to believe we're not responsible for Pittsburgh Corning's products, we feel this agreement will benefit our company and our shareholders in view of the number of claims and runaway verdicts against other companies."

Shares of Travelers gained 27 cents to close regular-hours trading at $19.00 before the after-market announcement of settlement, while shares of PPG gained $1.30, or 7 percent, to $57.10