California grape growers, given the choice by the Environmental Protection Agency of certifying that their grapes meet EPA standards for potentially hazardous sulfur dioxide or simply telling the consumer they were treated with the chemical, have decided to let the buyer beware.

As a result, 20 percent of the bunches in each treated box of California table grapes sold in supermarkets after Sept. 1 will bear tags saying that the "grapes have been treated with sulfites," the California Table Grape Commission told the EPA yesterday. The label will permit grapes to be sold regardless of sulfite residue levels and will be followed by the phrase "to ensure freshness and quality."

Sulfur dioxide, a sulfiting agent and post-harvest fumigant, has been used widely on table grapes to prohibit bunch rot. The Food and Drug Administration banned the use of sulfites as a preservative on fresh fruits and vegetables last July, but the regulation did not apply to the use of sulfites as fungicides, a category regulated by EPA. Last December the EPA established an interim tolerance level for the sulfur dioxide residue of 10 parts per million.

According to FDA reports, sulfite treatments on other foods have been suspected in 16 deaths and more than 800 allergic reactions. Those who are sulfite-sensitive are primarily asthmatics. The FDA has no reported incidents of allergic reactions from grapes, which have been treated with sulfur dioxide for more than 60 years, according to grape growers.

During August and September grapes receive multiple treatments of sulfur dioxide so they can be stored for long periods. After three or more treatments residue levels may exceed 10 parts per million, according to the commission. To avoid illegality, the California group asked the EPA last month for a waiver of the rule.

Anyone selling grapes in this country has been given the same options by the EPA: certifying that the residues don't exceed those levels, placing warning placards in supermarkets or labeling 20 percent of the bunches in a box. There are 20 to 30 bunches in a shipping box.

About 96 percent of the grapes grown in the U.S. come from California and are sold in the late spring, summer and fall. Imported grapes, mostly from Chile, are sold here from January to May. Over the past year, Chilean grape importers have been operating under a successful certification program, according to the FDA.

"We are disappointed that the EPA was not able to bite the bullet and require certification," said Karen Brown, spokesperson for the Food Marketing Institute, which represents U.S. supermarkets.

Mitch Zeller, an attorney with the Center for Science in the Public Interest, said he is concerned that labeling only 20 percent of the bunches would make consumers think the unlabeled grapes did not contain sulfites, and that the phrase "ensures freshness and quality" would make shoppers think the sulfite-treated grapes were superior.