New York state and Suffolk County health officials are warning Long Islanders to avoid contact with the water from the Port Jefferson Harbor following a sewage spill Monday morning.

According to officials, 30,000 gallons of partially treated sewage spilled into the water after a 2-hour electrical malfunction of one of the UV disinfection units at the Port Jefferson sewage treatment plant.

"It was like green," Port Jefferson resident Gary Contes said. "I thought it was an oil spill or something."

The plant is back up and running normally, but the damage was already done.

"The air is still cool and the water cold, so we don’t expect many people to be recreating in the harbor," Suffolk County Health Commissioner Dr. Gregson Pigott told News 12 in a statement. "But out of an abundance of caution, we are warning those who may choose to fish, canoe or recreate at the water’s edge to take steps to protect themselves and their families from potential pathogens."

Without disinfection, partially treated sewage carries high levels of bacteria and viruses.

Suffolk County health officials are advising people to avoid contact with water from the entire Port Jefferson Harbor Complex until 9 a.m. tomorrow. This area includes the Setauket Harbor, the Narrows and Conscience Bay in the town of Brookhaven.

Health officials warn people to immediately rinse down with clean water if they come in contact with the harbor and keep children and pets away from the area.

"It definitely is life-altering because so many spend time down here," Port Jefferson resident Dave Burnham said.

People are told to seek medical attention if exposed to the contaminated water and experience nausea, vomiting, diarrhea, skin, eye or throat irritation, allergic reactions or breathing difficulties.

"It's important that we keep the water as clean as possible," Port Jefferson resident Peyton Hanko said.

The New York Department of Environmental Conservation said the spill affected 1,639 acres of shell fishing beds. The state added that shell fishing is closed until further notice due to an increased risk that the shellfish could be hazardous to eat.