Colorado Parks and Wildlife warns of blue-green algae bloom at John Martin Reservoir State Park

Colorado Parks and Wildlife is warning visitors to avoid contact with the water at a state park in southeast Colorado due to blue-green algae.

Routine water sampling at the west boat ramp cove at John Martin Reservoir State Park recently detected algae toxin levels above the threshold for recreational water contact. CPW says it has put signs in place in the affected areas warning visitors and their pets to stay out of the water until it's safe.

At high concentrations, blue-green algae, or cyanobacteria, can cause rashes, gastrointestinal issues, muscle weakness, or even vomiting. They can be particularly harmful to pets. Those blooms can resemble thick pea soup or bluish-green paint spilled on the water's surface. They can also look like a thick mat of foam along the shoreline or short grass clippings.

Anglers should also avoid contact with areas where the algae is visible, and CPW said anyone who comes in contact with the algae should rinse thoroughly with clean water as soon as possible.

Officials say water testing at the east boat ramp found no signs of algal toxins. Water from Lake Hasty has also remained below the recommended threshold.

The Colorado Department of Public Health and Environment's Toxic Algae Dashboard shows current notices or warnings in bodies of water across the state.