The state Department of Health is investigating an apparent cleanup of the Duke Kahanamoku Lagoon by the Hilton Hawaiian Village after complaints of odor from the lagoon.

“DOH was informed that there have been several complaints about odor from the lagoon,” DOH spokeswoman Janice Okubo said in an email. “As DOH understands, Hilton Hawaiian Village has been preparing the hotel to reopen and doing some work at the lagoon.”

The Waikiki resort, which has been closed due to the COVID-19 outbreak in Hawaii, is reopening on Dec. 15 and accepting reservations. The lagoon sits between the resort and Duke Kahanamoku Beach.

A video posted Thursday on the Instagram account hohungryhungryhawaiian, which is private, shows a machine at the lagoon pumping what appears to be sludge into trenches in the sand at the beach, just a few yards away from beachgoers.

The hand-held video shows the dark green liquid flowing through a hose from the lagoon into the trenches.

By Friday evening, there was no pump or hose, and there was no sign of sludge or trenches in the sand as shown in the video. However, an odor from the lagoon has persisted.

Okubo said the health department has not been able to get in touch with hotel management but said an investigation has been opened to explore possible violations.

Hilton Hawaiian Village was not immediately available for comment.