An Ontario beach just shut down for the fourth summer in a row due to the presence of a toxic algae, which can cause skin irritation, nausea, and diarrhea if touched or ingested. 

In a news release on Thursday, the City of Hamilton announced that Hamilton Public Health Services had shut down Pier 4 Park Beach due to the confirmed presence of toxin-producing blue-green algae (cyanobacteria). 

Blue-green algae are microscopic, plant-like organisms that occur naturally in lakes, ponds, rivers, and streams. They typically thrive in areas where the water is shallow, slow-moving, and warm. 

Adverse health effects are usually caused by drinking water that is contaminated with blue-green toxins, and may include skin irritation, rash, sore throat, sore red eyes, swollen lips, fever, nausea, vomiting, and/or diarrhea. 

Hamilton Public Health Services has closed Pier 4 Park Beach due to the confirmed presence of toxin-producing blue-green algae (cyanobacteria).

Release >> https://t.co/vnKuoxxnSN #HamOnt pic.twitter.com/94Cv1OqSeo

— City of Hamilton (@cityofhamilton) July 4, 2024

The City is advising all residents and visitors to avoid contact with the water along the shoreline of Pier 4 Park Beach and to not swim or wade in any areas where blue-green algae is visible. 

Luckily, the presence of blue-green algae at Pier 4 Park Beach does not affect the safety of Hamilton's drinking water, although this confirmation means there are currently no safe swimming beaches in Hamilton Harbour. 

The nearby Bayfront Park Beach, which shuttered in 2016, remains closed due to a history of poor water quality. 

Warning signs at Pier 4 Park Beach will be posted, and the closure will remain in effect until the toxic blue-green algae subsides.