New research from Stony Brook University has found evidence of flesh-eating bacteria in several bodies of water across Long Island, including Sagaponack Pond, Mecox Bay and Georgica Pond on the South Fork.

Stony Brook University Professor Chris Gobler said the bacteria pose a serious health risk, particularly during the summer months.

“People who are infected with this bacteria have a 20% chance of dying within just 48 hours following infection,” Gobler said.

Gobler said additional waters, including areas in East Quogue, are also contaminated with bacteria that poison shellfish. He noted that dozens of bays and ponds across Long Island contain toxins linked to harmful algae blooms.

“If someone’s immunocompromised and or elderly and they have open wounds in summer, at least you may want to stay out of the water,” Gobler said.

Residents near affected waterways say the water has changed over the years.

“I live here in East Quogue on the water and it is upsetting because it’s not as usable as it used to be,” said Richard Dietz, who lives along the shoreline.

Gobler said the primary cause of the contamination is years of nitrogen runoff entering Long Island’s waterways.

“The major source of nitrogen coming from land to sea is what we call onsite septic systems,” Gobler said. “Suffolk County is largely unsewered.”

Researchers at Stony Brook say one potential solution involves expanding the use of shellfish and seaweed to absorb excess nitrogen from the water. Suffolk County officials say efforts are also underway to address failing infrastructure.

“It’s a 35-year program that the county’s embarked upon to remove 360,000 cesspools and non-functioning septic systems,” said Jennifer Juengst, Suffolk County’s deputy county executive.

In the meantime, Stony Brook researchers are urging the public to remain cautious and stay informed.

The university advises residents to watch for water advisories this summer that indicate where it is safe to swim.