Toronto’s health department is warning the public about the presence of potentially toxic algae in Humber Bay East.

Officials say water samples taken from the mouth of Mimico Creek and in Humber Bay Park East in recent weeks have tested positive for blue-green algae blooms, known formally as cyanobacteria.

Toronto Public Health (TPH) was advised by the Ministry of the Environment of its presence and is warning residents to avoid the contaminated water.

Though it occurs naturally, the plant-like organisms can produce toxins that are harmful to humans and animals.

“It’s common in Ontario but it’s the first report that I’ve heard about in Toronto in quite some time,” Dr. Howard Shapiro, the city’s associate medical officer of health, said Tuesday.

“Right now the area that they tested is fairly small. Beside Mimico Creek, there’s a little ponded area and I think also a little bit in the creek as well. It’s fairly restricted at this point.”

The algae are common in the late summer months and typically thrive in shallow, slow-moving water.

According to the Ministry of Environment, the algae can range in colour from olive green to red but often look like “green pea soup.”

The blooms, if fresh, “often smell like newly mown grass while older blooms may smell like rotting garbage.”

“It can look like different things. It can be a film that’s kind of green over the water, it might be blueish in colour as well, but also more of a mat on the surface of the water,” Shapiro said.

Exposure to the algae can cause a spate of health problems, TPH says. Anyone exposed to the bacteria could experience headaches, fever, skin rashes, abdominal pain, nausea or diarrhea.

The health department is advising citizens and their pets to be cautious near this part of Toronto’s waterfront and to avoid entering the specific section of Mimico Creek.

“Our message is – if the water doesn’t look clean, if it looks like algae or discolouration, stay out of it and make sure your pet also stays out of it,” Shapiro said, adding that consuming the water would put people at serious risk of illness.

“There are efforts to try and do things that limit the growth of it, but it’s really not something where you can go in and intervene once it’s there.”

Anyone who does come in contact with the contaminated water is urged to wash off as soon as possible with clean water and contact their health care provider.