OLYMPIA — The state will dye waters around Whidbey Island red to test safety of shellfish growing areas.

The state Department of Health (DOH) will work Friday through Wednesday to evaluate wastewater movement near the newly reconstructed Oak Harbor Clean Water Facility (CWF) and its potential impacts on nearby shellfish growing areas.

Red dye will be added to the water on Monday morning and may be visible in and around Oak Harbor for roughly 24 hours.

The fluorescent dye — rhodamine — is a non-toxic dye approved by the Environmental Protection Agency (SPA) and Food and Drug Administration that is not harmful to people, marine life of the environment, DOH said.

DOH and FDA scientists will add the dye to treated wastewater from the facility and track the water’s movement.

The primary goal of the study is to evaluate the plant’s potential impact on the Saratoga Passage and Penn Cove growing areas.

Construction on the CWF was completed in 2019. The dye study was originally scheduled for 2019 but was delayed due to technology issues and delayed again in 2020 and 2021 due to the COVID-19 pandemic.

The study is a partnership between DOH, FDA, the state Department of Ecology, the City of Oak Harbor, Island County, and local shellfish growers.

DOH is responsible for the safety of commercially harvested shellfish in the state. For information on current advisories, visit the Washington Shellfish Safety Map, which is updated daily on the DOH website at doh.wa.gov.