Throughout the summer, National Park Service staff sample and analyze the Blue Mesa Reservoir water for the presence of blue-green algae containing cyanotoxins. The latest testing revealed that concentrations of the harmful algae within the Iola Basin exceed public health safe exposure levels.
Toxins were found at North Willow East, on the east side of Sometimes Island, and that general location has been posted with warning signs. Due to shifting winds and currents, other areas in the Iola Basin of Blue Mesa Reservoir may also contain these toxins, and notification signs have been distributed to heavily used visitor areas in the basin. The park staff advises to avoid areas with suspected algal mats in this area, and throughout the reservoir.