State park officials have been forced to shut down a popular vacation spot in the Hudson Valley ahead of the Fourth of July holiday due to an out-of-control algae bloom.

Harriman State Park Officials say 20,000 people were expected to be at Lake Welch this weekend. Junior Rosario was all set to show his girls his old vacation spot but had to change his plans.

"It's been 40 years," says Rosario. "I was 7 years old when I last stepped here. So, today I'm here now and unfortunately it's closed."

State park officials say an algae bloom has spread throughout the lake. They say some species of algae can kill animals and make humans sick.

Workers suggest that vacationers head to other nearby lakes like Lake Tiorati or Rockland Lake.

A state park spokesperson says it's tough to say when Lake Welch will reopen. He says once there are no visible signs of algae for at least a day, the Department of Environmental Conservation will test the water. If the tests come back clear for toxins, the lake will reopen.

Some employees might also be reassigned to other beaches where vacationers are being told to go to help with crowding.