The Rural Fire Service in New South Wales is investigating an incident where a helicopter dumped sewage on firefighters near Port Macquarie.
The ABC reports a chopper scooped sewage out of a treatment pool near Kew while firefighting last week.
RFS regional fire controller Cam Baker said about 30 volunteers and State Forest firefighters were drenched with contaminated water.
Inspector Baker said it was not a matter of a fire fighting operation going wrong.
"The aircraft will always go to the nearest water source at the initial stage of the fire," he said. "Those types of treated water have been utilised before for fire fighting operations,"