COLORADO SPRINGS, Colo. (CBS4) – Prospect Lake is closed in Colorado Springs after water samples tested positive for blue-green algae. Officials with the Colorado Department of Health and Environment say the bacteria can be harmful to humans and pets.

Windsor Lake was closed for a week in late July after water samples tested positive for blue-green algae. The bacteria is common in lakes throughout Colorado, according to health officials. The algae multiply rapidly to form blooms and scums and are impacted by a combination of sustained hot weather, stagnant water, and polluted stormwater runoff.

In North Carolina, a woman is warning pet owners after her three dogs died hours after a swim in a pond filled with the toxic algae. Melissa Martin said her dogs began having seizures after returning from the pond in Wilmington.

“At 12:08 a.m., our dogs crossed the rainbow bridge together,” Martin told CBS affiliate WWAY. “They contracted blue-green algae poisoning and there was nothing they could do. We are gutted. I wish I could do today over. I would give anything to have one more day with them.”

After consulting with health officials, Martin’s vet said her dogs were poisoned with lethal blue-green algae –– known as cyanobacteria –– that resulted in her having to put them down.

“He came onto the floor and he was trying to wrap his paw around my arm and I just told him what a good boy he was and that we weren’t going to let this happen for nothing,” said Martin.

Colorado health officials have posted signs banning swimming, bathing, paddle boarding, and water activities at Prospect Lake. Rentals are not available, and no pets are allowed. Fishing areas will remain open, but anglers are urged to clean fish well and remove guts.

“Given today’s positive test for mycrocystin toxin, we have closed Prospect Lake for usage,” said Erik Rodriguez, health, safety and environmental specialist with the Parks, Recreation and Cultural Services Department. “CDPHE will continue to test weekly until the bacteria clears up.”

While visitors are advised to stay out of the water, other amenities at Memorial Park are still open.

For more information, visit www.coloradosprings.gov/memorialpark.