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Toxin-producing blue-green algae (Cyanobacteria) present along the western shoreline of Hamilton Harbour, Bayfront Park Boat Launch, Bayfront Park Beach, and Pier 4 Beach

Hamilton, ON - July 12, 2017 - Public Health Services has confirmed the presence of toxin-producing blue-green algae (Cyanobacteria) at the Bayfront Park Boat Launch, Bayfront Park Beach, and at Pier 4 Park Beach. Observations by Public Health Services staff indicate that blue-green algae are also present along most of the western shoreline. The algae is present from the inner Pier 8 area, through the marinas, and to the closed waterfront trail.

Bayfront beach was closed in 2016 due to chronically poor water quality. Pier 4 beach is closed due to high water levels. The public are urged to not enter and avoid contact with the water along the western shoreline of Hamilton Harbour. Contact with the water while launching or trailering watercraft should be avoided. People who come into contact with the water should wash themselves off as soon as possible with clean water. Facilities for hand washing and rinsing off are available at the Bayfront Park Public Washrooms. The washrooms are located at the east side of the Bayfront Park parking lot. Pets should also be kept out of the water.

The concentration of microcystin (toxin) in the water was tested at Bayfront Park Boat Launch, Bayfront Park Beach, and Pier 4 Beach. All three locations had greater than 10 parts per billion of microcystin.

The safety of Hamilton’s drinking water supply is not affected by this situation.

Health effects

Some blue-green algae have the potential to produce toxins or skin irritants. Adverse health effects are mainly caused by drinking the water that is contaminated with blue-green algae toxins. Skin contact with blue-green algae contaminated water can cause skin irritation and itching. Exposure to blue-green algae toxins, if present in sufficient amounts, can cause:

  • Headaches
  • Fever
  • Diarrhoea
  • Abdominal pain
  • Nausea or vomiting
  • Skin rashes
  • Mucous membrane irritation

Anyone who has recently been in direct contact with the waters along the western shoreline of Hamilton Harbour and is experiencing headaches, fever, diarrhoea, abdominal pain, nausea or vomiting is advised to contact their primary care provider (family physician, nurse practitioner or walk-in clinic).

Additional resources

For the current status of the water quality at Hamilton beaches, call the City of Hamilton Public Health Services Safe Water Infoline at 905-546-2189 or visit  

More information about blue-green algae can be found on the Health Canada website (PDF, 1.1 MB).