Unum Group Corp. has paid about $676 million in extra benefits to claimants in connection with a review of past claims decisions, officials say.

Unum, Chattanooga, Tenn., has paid the benefits in the course of completing a claims reassessment process required by the state insurance regulators that have been participating in a large, multi-state examination of the company’s handling of disability claims.

In addition to reviewing past claims, Unum “has instituted policies and procedures to ensure its claimants are treated fairly going forward,” Massachusetts Insurance Commissioner Nonnie Burns says in a statement.

Massachusetts has been one of the 4 states helping to lead the multi-state exam process. The other lead states are Maine, New York and Tennessee. Those states and the U.S. Department of Labor negotiated the multi-state settlement agreement with Unum in 2004.

The agreement, endorsed by 48 states and the District of Columbia, required Unum to review claims processed between January 1997 and 2004, improve procedures for handling future claims and strengthen quality control systems.

Examiners believe Unum has complied with the terms of the agreement, Massachusetts officials say.

The claim reassessment process reversed, in whole or in part, about 42% of the claims reassessed, according to officials in Maine.

The case “is an excellent example of effective state-based insurance regulation for insurance consumers,” Maine Insurance Superintendent Mila Kofman says in a statement. “Regulators identified a problem and worked together to effectively address it.”