An EPA alert for Williamstown beach was removed on Friday after orange discoloured water was found to be an algal bloom.
The EPA issued an alert on Thursday warning people not to swim or make contact with water at the beach until further notice.
The spread of orange-coloured water was in front of the Williamstown Swimming and Life Saving Club.
EPA test results have revealed the algae was most likely a Noctilucasp bloom.
Lead agency, Department of Environment, Land, Water and Planning (DELWP), said algal blooms were rarely harmful to people.
It received no reports of illness or injury from using Williamstown beach on Thursday.
DELWP regional manger Rod Anderson the algae was no longer visible or present in the area.
“Algal blooms are natural occurrences that can form in Port Phillip Bay under certain conditions, particularly when the weather warms,” he said.
“They usually dissipate within a few days and in this instance it appears the tides and currents late yesterday afternoon and overnight broke the bloom down naturally.”
