The Agriculture Department announced yesterday that -- except for some bacon -- meats such as ham, sausage and hot dogs that are cured with nitrites do not form cancer-causing nitrosamines when cooked.

In the case of bacon, the department proposed to add the "dry-cured" variety to its program that monitors nitrosamines in the nation's biggest-selling bacon, called "pumped" bacon. Virginia is the nation's largest producer of dry-cured bacon, at 1.5 million pounds per year. Data on another type of bacon called "immersion cured" were inconclusive, the department said.

The announcement, which followed three years of study, lifts the cloud of worry that descended on all cured meats in 1976 when studied linked nitrites with the formation of the carcinogenic nitrosamines as bacon cooked.

Sodium nitrites are either injected, rubbed into or soaked into meat to prevent botulism, a deadily food contaminant.

The 1976 studies of injection-cured, or "pumped," bacon, which forms the bulk of the U.s. market supply, found that nitrites in it combined with amines, or proteins, in the meat to form nitrosamines. Further research on other cured meats began at once.

Assistant Agriculture Secretary Carole Tucker Foreman said that the meat industry's Nitrite Safety Council and the Agriculture Department both found that "a significant proportion of dry-cured bacon appears to be adulterated with confirmable levels of nitrosamines."

However, the researchers found that other cured meats -- even when fried, broiled, baked, roasted or cooked in microwave ovens -- showed no traces of nitrosamines. The studies cover ham, corned beef, pork shoulders and bellies, bologna, hot dogs and other sausages, including pepperoni and Genoa sausage, said Foreman's deputy, Sid Butler.

"Essentially we've given a clean bill of health to every cured meat product except bacon," he said.

The dry-cured variety, in which nitrites, salt and spices are rubbed into the bacon and left to cure for varying lengths of time, is produced in 25 states, but accounts for only 1 percent of the market. Foreman said. The E.M. Todd Co. of Richmond is Virginia's largest producer.

Butler emphasized that individual processing plants may vary in their procedures and that many showed no trace of nitrosamines in their bacon. Still, under yesterday's proposal, dry-cured bacon would be added to ongoing monitoring programs for injection-cured bacon.

Those involve spot checks for packages at each plant. Any batches that show more than 10 parts per billion of nitrosamines are withheld from the market.

Foreman stressed that the studies concerned only nitrosamine formation, and not involve any evaluation of the safety of the nitrites themselves, which some researchers have said may also cause cancer.