Wastewater from the public restrooms at Sharks Cove on Oahu's North Shore is seeping into the tide pools, a finding that is bad news for swimmers, snorkelers, and marine life at one of Hawaii's most visited beaches.

• Non-toxic green dye flushed through the park bathrooms showed up in the tide pools below, confirming a groundwater link that locals had suspected for years.
• Researchers will now sample the spots with the most dye and test for fecal bacteria, nutrients, and other chemicals that could harm people or sea life.
• How serious the pollution is remains unknown, and the results will decide whether the wastewater system gets changed or other protections are put in place.
• Visitors are confused, with some being told to just avoid the green patches in the water.
• The Hawaii Department of Health has not issued a health warning for Sharks Cove, but it will send an alert if bacteria levels test as dangerous.

Outlook: Lab results are expected to determine how badly the water is contaminated and what fixes to the restroom wastewater system come next.