A union representing DuPont Co. workers has filed a class-action lawsuit claiming the company has failed to correct miscalculations of pension benefits for employees who retired on or after Aug. 1 last year. The International Brotherhood of DuPont Workers filed the lawsuit Monday in U.S. District Court in Richmond on behalf of five people who recently retired, or soon will retire, from four DuPont plants, including the company’s Spruance plant in Chesterfield County.

The slowdown in everything from construction to automobile sales and consumer spending has rippled across manufacturing jobs at one of the Richmond area’s largest employers.

The worst seems yet to come this economic recession, though declines in gasoline prices and mortgage rates offer signs of hope, one corporate economist said yesterday. “We think [this recession] is probably going to be on the same order of magnitude as the 1981 to 1982 recession and the 1973 to 1975 recession,“ said Robert C. Fry Jr., senior associate economist for DuPont, the Wilmington, Del.-based industrial giant and a major employer in the Richmond area.