Warning signs are being posted this morning and the public is advised to stay out of Palolo Stream, the Ala Wai Canal and waters off Magic Island and Ala Wai Yacht Harbor after 1,200 gallons of wastewater spilled from a manhole on 9th Avenue Monday night.

The state Department of Health's Clean Water Branch says an estimated 700 gallons flowed into Palolo Stream, which connects to the Ala Wai Canal.

The overflow was caused by grease that had clogged an 8-inch main.