Blue-green gross-out: What is toxic algae, why it blooms and what we can do about it

Every summer several Washington lakes and river sections, including a few at state parks, close due to toxic algae blooms. Not only is this gross and annoying – especially when your vacation is already planned – but blooms can pose serious health risks to people and pets. 

Toxic algae blooms are microscopic organisms that grow quickly, or “bloom” in a lake or reservoir.