Warning signs were posted yesterday and the public is advised to stay out of Pālolo Stream, the Ala Wai Canal and waters off Magic Island and Ala Wai Boat Harbor after 1,200 gallons of wastewater spilled from a manhole on Ninth Avenue Monday night.

The state Department of Health's Clean Water Branch said an estimated 700 gallons flowed into Pālolo Stream, which empties into the Ala Wai Canal.

The overflow was caused by grease that had clogged an 8-inch main, the city said.