WASHINGTON (AP) _ The government began attempts Tuesday to identify an estimated 40,000 workers believed eligible to share in about $100 million from pension plans terminated between 1976 and 1981.

The effort follows tentative settlement last December of a class-action suit brought against the Pension Benefit Guaranty Corp., the government's pension insurance agency.

Plaintiffs included former workers who participated in about 11,000 mostly small-company pension plans, but who were denied benefits after the plans collapsed because of a dispute over vesting.

Under the settlement, workers with at least 10 years of service would receive lump-sum payments equal to about 80 percent of what they were due when their funds collapsed. Smaller amounts would go to employees with between five and 10 years service.

The PBGC said it was mailing a claims form and other material to about 135,000 people known to have participated in the plans to determine those eligible to share in the settlement.

The mailing also will include information about a June 3, 1996, court hearing at which a final settlement will be sought.

The government pension insurance agency also plans to place ads in about 700 Sunday newspapers and other periodicals in April. The ads will include forms to be used to determine eligibility.

The PBGC said people also can obtain information about the settlement by calling 1-800-316-8857, the toll-free number operated by the attorneys who represent the class.