AKRON, Ohio (AP) _ The 4,700 Firestone Inc. workers were returning to work in six states today after company and union negotiators reached a tentative agreement that ended a week-old strike.

Meanwhile, a contract covering 15,000 Goodyear Tire & Rubber Co. workers was ratified Sunday when a local in Akron approved the agreement, United Rubber Workers union officials said.

A tentative agreement was reached Tuesday, and nine of 11 Goodyear locals have approved the contract. One local rejected it and workers in Gadsen, Ala., vote today, union spokesman Curt Brown said.

Union officials were optimistic about the Firestone agreement reached early Sunday, but some workers remained suspicious as they beagn returning to work night.

''There are a lot of people uneasy about it, going back to the plant and building up (an inventory of) tires without knowing what's going to happen in a couple of weeks,'' said union member Dan Hook in Des Moines, Iowa.

The URW struck Firestone May 15 after the company refused to accept the cost-of-living allowance provided in an industry pattern agreement the union negotiated with Goodyear.

The three-year Firestone contract followed the revised Goodyear pattern, Brown said.

George W. Aucott, who heads Firestone's tire operations, called the agreement ''fair and realistic,'' and added that it ''recognizes the particular needs of Firestone's tire operation.''

The Firestone agreement would:

-Maintain cost-of-living allowances in each year, with a 1-cent increase for every increase of 26-hundredths of a point in the Consumer Price Index.

-Boost wages 25 cents per hour by deducting that amount from future cost- of-living adjustments in increments of 10 cents, 10 cents, and 5 cents.

-Increase retirement pensions for current workers by $3.50 to $23.50 per month for each year of service. In addition, current retirees would receive a lump sum bonus of $200 before Dec. 1.

The pact also assures continuation of the contract if a Firestone plant is sold to another company during the next three years, and contains a no-strike wage reopener clause in the third year.

Ratification votes on the Firestone pact should be held this week at company offices and plants in Akron; Noblesville, Ind., Des Moines, Iowa; Decatur, Ill.; Russellville, Ark.; and Oklahoma City, Brown said.

The Des Moines, Decatur and Oklahoma City plants make tires; the Noblesville plant makes molded rubber products, and the Russellville plant makes innertubes.