Following a chemical treatment aimed at controlling aquatic vegetation in Port St. Lucie’s Elkhorn Canal, residents reported what they called the “worst smell in the entire world” as countless fish perished on the canal’s surface. Water tests revealed that dissolved oxygen levels plunged to levels unsustainable for aquatic life—an unintended but severe consequence of the applied chemicals.
Critics argue that proper dissolved-oxygen testing should have been completed before treatment—something the contractor failed to do. Environmental advocates now recommend exploring safer alternatives, such as mechanical harvesting or biological controls, to manage vegetation without triggering oxygen depletion or fish kills.