DENVER (KDVR) — Parts of the Cherry Creek Reservoir are closed to recreation due to toxic blue-green algae bloom.

Colorado Parks and Wildlife said swimming, paddleboarding and wading will not be allowed near the marina and West Shades area of the reservoir. However, boating and fishing will still be allowed.

Signs have been placed in the areas to inform people of the closure and warn about the dangers of coming into contact with an algae bloom.

“We tell people, if in doubt just stay out of the water, that’s the safest thing and please heed the warnings when you see people talking about staying out of the water,” Colorado Department of Public Health’s Clean Water Program Manager Nathan Moore said. “These algae produce toxins, and those toxins can be harmful both on the short term causing things like skin irritation and upset stomach. But they can also have long-term impacts on people causing kidney damage. And they’re specifically dangerous to pets.”

Recreation is closed when water tests above 8 micrograms per liter of the toxic algae microcystin. That threshold is set by the Colorado Department of Public Health and Environment.