SACRAMENTO (CBS13) – With thousands of Californians hitting the state’s waterways this Labor Day, officials are warning of algae blooms in the water that are harmful to humans and animals.

According to the State Water Resources Control Board algae is known to cause irritation to the respiratory system, skin, eye, and throat discomfort, vomiting, and gastrointestinal distress. It can also cause vomiting, difficulty breathing, seizures, and sometimes death — especially in dogs. Dogs and kids are particularly vulnerable because they are more likely to swallow water when swimming or playing. Algal blooms can be identified, typically, by their green, streaky appearance in the water, but sometimes can appear as other colors.

An algal bloom at the Stockton Waterfront.

Water samples have been gathered at popular lakes and streams with a history of harmful algal blooms throughout California as part of an effort to educate the public.

You can find an online interactive map, here, with information about waterways and bodies of water that have advisories due to harmful algal blooms.

LINK: Harmful Algal Blooms Map

The Water Boards have ramped up testing for the harmful blooms in advance of the Labor Day weekend and posted information about water bodies that have advisories on a harmful algal bloom portal. The portal offers information on which tested waterways offer safe recreation options and which ones require caution.