For people who live in coastal areas, harmful algal blooms, or HABs — sometimes called red tides, because they can turn seawater a deep red — are an increasingly frequent threat, thanks to climate change. HABs produce toxins that cause mass fish kills and make shellfish risky to eat. In rare instances, they can cause life-threatening respiratory illnesses in humans, and also make the surrounding air more difficult to breathe.

But as it turns out, you may be at risk of exposure to the algae that cause red tides even if you don’t go anywhere near the beach. The possible point of exposure is a home aquarium.

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In a study just published in the journal Environmental Science & Technology, Italian researchers detected the presence of high levels of the palytoxin and hydroxypalytoxin, two chemicals secreted by HABs, in a saltwater aquarium found in a home where an entire Dutch family of four suffered respiratory distress, fevers, nausea and flu-like symptoms. The toxins were found in soft coral and seawater from the aquarium, according to the study.

The presence of those hazardous chemicals provides an explanation for other anecdotal reports of aquarium owners becoming ill, according to the study. The illnesses occurred after the owners used hot water to clean their tanks. Apparently, hot water making contact with aquarium rocks creates steam that releases the toxins into the room’s air, where they can be inhaled by unwary occupants.

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If there’s some good news here, it’s that the hazard can now be identified. Lead researcher Carmela Dell’Aversano and colleagues developed a test that can quickly determine if the toxins are present in an aquarium.