A wave of drug overdoses in Georgia has killed as many as four people and hospitalized dozens over two days, health officials said on Tuesday.

Christopher Hendry, the chief medical officer at Navicent Health, a hospital in Macon, said at a news conference that officials believed the spate of overdoses was linked to yellow pills that users bought on the street. He noted, however, that toxicology reports will not come back for a few more days, so the causes of the deaths have not been confirmed.

“There is a new drug that’s surfaced in our community,” he said. “It’s being sold on the street as Percocet, however, when it’s taken, the patients are experiencing significant and severe decreased levels of consciousness and respiratory failure.”

In a statement, the Georgia Department of Health said while the overdoses were reported in south and central Georgia, the drugs may also have been sold in other parts of the state.