Members of Congress, scientists and consumers accused the Food and Drug Administration yesterday of failing to act promptly to protect the public against sulfites, despite reports linking the widely used preservative to 12 deaths and more than 500 adverse reactions since 1982.

"What we have here is a case of a sleeping government watchdog," Rep. Ron Wyden (D-Ore.) said at a House Energy and Commerce oversight hearing.

Wyden said sulfites are the "only food additive tied to fatalities in the last 20 years" -- one of them the February death of a 10-year-old Oregon girl who had eaten guacamole and salad overloaded with sulfites to keep the foods looking fresh.

"These minor benefits are not worth the risk," said subcommittee Chairman Rep. John D. Dingell (D-Mich.).

"The amount used in restaurants is large and essentially uncontrolled."

Both Wyden and Dingell supported a limited ban on the use of sulfites in fresh fruits and vegetables and cut or frozen potatoes, an approach they said was endorsed earlier this year by an outside scientific committee advising the FDA.

Wyden, who recently proposed such a legislative ban with Sen. Albert Gore Jr. (D-Tenn.), said congressional action wouldn't be necessary if the FDA had followed this advice.

Gore testified that "ironically the business community has been beating on FDA's door asking for more regulation."

The National Restaurant Association said in a statement yesterday that it has supported such a ban as "a sound solution to a very serious health-related problem."

Dingell derided the FDA's request to the states for voluntary posting of warning placards in restaurants as inadequate.

"If sulfites pose a risk sufficiently great to require a skull and crossbones on the front door of a restaurant, then they should not be used inside," he said.

An estimated 15 percent of restaurants use sulfites.

Although sulfites long have been used in foods, drugs and wine, recognition of the problem is relatively recent.

Scientific estimates differ, but the FDA agrees that 5 percent to 10 percent of the nation's 9 million asthmatics may be particularly sensitive to the chemicals, although nonasthmatics also may suffer adverse reactions. The problems range from rashes to severe shock reactions soon after ingestion that can result in coma, brain damage or death.

"The Food and Drug Administration has systematically mishandled the sulfite problem and has displayed a callous disregard for the public's health," charged Michael F. Jacobsen, director of the Center for Science in the Public Interest, a consumer group that petitioned the FDA in October 1982 to ban or severely restrict the use of sulfites in food and drugs.

Scientific and consumer witnesses at yesterday's hearing generally agreed that a ban on restaurant uses, particularly in salad bars, was needed because customers often do not know they are at risk and restaurants may not know if their food has been treated with sulfites.

Although these uses are largely cosmetic, Dingell noted that in other cases in which sulfites are used to preserve drugs and processed foods, "the labeling approach to sulfites seems to make more sense."

FDA Commissioner Dr. Frank E. Young yesterday defended the agency's efforts to date, but admitted that "we now need to look at other options."

Although Young's testimony made no mention of it, internal documents made public at the hearing showed that last year the FDA proposed two labeling regulations that have not been been acted upon by the Reagan administration.