Hamilton Public Health (HPH) has shut down the city’s Pier 4 Park Beach after it was confirmed that toxin-producing blue-green algae was located there. Known as cyanobacteria, this bacteria can cause various adverse health effects, which are most often caused by drinking contaminated water. Those who come into contact with the visible blue-green algae or ingest water containing it may experience skin irritation, rash, sore throat, sore red eyes, swollen lips, fever, nausea, and vomiting and/or diarrhea. The health unit is urging anyone who has recently been in direct contact with waters at Pier 4 Park Beach and is experiencing headaches, fever, diarrhea, abdominal pain, nausea or vomiting to contact their primary care provider like their family physician, a nurse practitioner, or a walk-in clinic. Stay away from Pier 4 Beach shoreline: public health Further, people are being urged to stay away from the water along the shoreline of Pier 4 Beach. Anyone who comes in contact with the water there, should wash themselves off as soon as possible with clean water. People are also being advised to not swim or wade, or allow your pets to swim or wade, in any areas where blue-green algae may be visible. Warning signs posted at Pier 4 Park Beach The health unit said beach operators will be posting warning signs at the beach, which will be closed until the blue-green algae subsides. In the meantime, HPH said they will continue to monitor, gather water samples, and provide online updates. “The presence of blue-green algae at Hamilton-area public beaches serves as a strong indicator that blue-green algae can be present within the broader watershed,” HPH said in a news release. Public health noted that the safety of the city’s drinking water is not affected by the confirmation of blue-green algae at Pier 4 Park Beach. Avoid contact with blue-green algae Public health says people should avoid being in contact with blue-green algae, which is naturally occurring and typically forms in shallow, warm, slow-moving or still waters. This bacteria spreads with temperature fluctuations, notably increased water temperature as well as with high-nutrient loads, water mixing, and slow-moving or still waters. Algae/vegetation in the water can give off an offensive odour as it dies and decays. This may be more prominent along the shoreline and in various “nooks and crannies” along the shoreline such as docks and boat slips. The health unit said locally, algae blooms have been observed until late November and/or early December.