On a July night in 1987, scores of elderly and chronically ill patients at Bird S. Coler Memorial Hospital in New York City began to fall violently sick with food poisoning from eggs tainted with salmonella.

“It was like a war zone,” said Dr. Philippe Tassy, the doctor on call as the sickness started to rage through the hospital.

By the time the outbreak ended more than two weeks later, nine people had died and about 500 people had become sick. It remains the deadliest U.S. outbreak attributed to eggs infected with the bacteria known as Salmonella enteritidis.

This year, the same bacteria sickened thousands of people nationwide and led to the recall of half a billion eggs.

Despite the gap of decades, there is a crucial link between the two outbreaks: In both cases, the eggs came from farms owned by Austin DeCoster, one of the country’s biggest egg producers.

DeCoster’s frequent run-ins with regulators over labor, environmental and immigration violations have been well cataloged. But the close connections between DeCoster’s egg empire and the spread of salmonella in the United States have received far less scrutiny.

While some state regulators took steps to clamp down on tainted eggs, the federal government was much slower to act, despite entreaties from state officials alarmed at the growing toll.

Farms tied to DeCoster were a primary source of Salmonella enteritidis in the United States in the 1980s, when some of the first major outbreaks of human illness from the bacteria in eggs occurred, according to health officials and public records. At one point, New York and Maryland regulators believed that DeCoster eggs were such a threat that they banned sales of the eggs in their states.

“When we were in the thick of it, the name that came up again and again was DeCoster Egg Farms,” said Paul Blake, who was head of the enteric diseases division of the Centers for Disease Control and Prevention in the 1980s, when investigators began to tackle the emerging problem of salmonella and eggs.

By the end of that decade, regulators in New York had forced DeCoster to allow salmonella testing of his farms and, along with other states, pushed the egg industry in the eastern United States to improve safety, which led to a drop in illness.

But the efforts were patchwork. For example, Iowa, where DeCoster has five farms tied to the current outbreak, required no testing.

And the federal government, at times under pressure from Congress and the industry to limit regulation, spent two decades debating national egg safety standards. New rules finally went into effect in July — too late to prevent the current round of illness.

Records released by congressional investigators last week suggest that tougher oversight of DeCoster’s Iowa operations might have prevented the outbreak, which federal officials say is the largest of its type in the nation’s history, with more than 1,600 reported illnesses and probably tens of thousands more that have gone unreported.

According to the records, DeCoster’s farms in Iowa conducted tests from 2008 to 2010 that repeatedly showed strong indicators of possible toxic salmonella contamination in his barns. Such environmental contamination does not always spread to the eggs, and it’s unclear what actions DeCoster took in response. However, when the Food and Drug Administration inspected the farms after the recalls, officials found unsanitary conditions and the presence of Salmonella enteritidis in barns and feed.

“It’s striking that he was part of the early phase of the epidemic and that there is now a problem on his farms in Iowa,” said Dr. Robert Tauxe, deputy director of the foodborne illness division of the Centers for Disease Control.