A $39 million sweetener for tobacco farmers has been placed in omnibus trade legislation awaiting Senate floor action.

Sponsored by Sen. Jesse Helms (R-N.C.), the provision was tucked into the bill just before the broader legislation won Senate Agriculture Committee approval.

Producer cooperatives repay the Agriculture Department for defaults on tobacco loans made to farmers who use their crops as collateral. Under the Helms amendment, the cooperatives would not have to make up the difference if the government exported the tobacco under one of its promotion programs and failed to recoup the amount of the loans.

Legislation approved in 1982 amid concern over health effects of smoking provides that programs to aid tobacco growers must involve "no net cost" to taxpayers.

The Congressional Budget Office estimated this week that the Helms provision of the trade bill would cost taxpayers $39 million over five years.

"This is the first I've heard of this," said John F. Banzhaf III, executive director of Action on Smoking or Health. "It's outrageous that they're trying to sneak in the back door . . . ."

Helms' office maintains that the measure is not an attack on the no-net-cost system, saying in a statement, "This amendment simply ensures that all commodities are treated equitably."