Blue Mesa Water Quality Advisory – Toxic Algae Found August 2025

The National Park Service (NPS) has issued a water quality advisory for the Blue Mesa Reservoir following the discovery of toxic blue-green algae. Throughout the summer, NPS staff have been conducting routine tests and analyses of the reservoir’s water. The latest results indicate that concentrations of harmful cyanotoxins within the Iola Basin have surpassed safe exposure levels for the public.

Blue-green algae, scientifically known as cyanobacteria, are capable of producing toxins that pose a risk to humans and animals. Exposure to these toxins can lead to a range of health problems, including skin irritation, nausea, and potential damage to the liver and nervous system. The NPS has not specified the exact level of cyanotoxins detected but has emphasized that it exceeds safe exposure thresholds.

The NPS has urged visitors to the Blue Mesa Reservoir to avoid contact with the water until further notice. This includes not only swimming and wading, but also activities that may cause water spray, such as boating or jet-skiing. The NPS will continue to monitor the situation and update the public on any changes. For more information, visitors can refer to the NPS website.