An estimated 3,600 gallons of wastewater were released Monday onto Waianuenue Avenue near the Ululani Street intersection in Hilo between noon and 6 p.m., according to a county press release issued Tuesday afternoon.
The wastewater overflowed from the building and sewer-cleanout at 261 Waianuenue Ave.
The overflow entered a storm drain inlet at the corner of Waianuenue Avenue and Kinoole Street, which is connected to the storm drain system that discharges into Hilo Bay.
The county Department of Environmental Management determined that the cause of the overflow is related to the accumulation of debris in the collection system, which then caused wastewater to back up until it overflowed from the building and sewer-cleanout onto Waianuenue Avenue.
Responding crews removed the accumulated debris to release the blockage and resume normal flow. They cleaned and disinfected Waianuenue Avenue from the point of the spill to the storm drain.
Warning signs have been posted at the shoreline entry points, and shoreline samples have been collected for laboratory analysis, according to the county.