Hornsby Council officers are searching for an unknown offender who polluted Castle Hill’s Pyes Creek with a red contaminant last month.
The red liquid which appears to be an oxide was flushed through the drainage system on September 27.
Council officers were on the scene within hours and pumped away the contaminant from the creek.
They’re calling on anybody with information to come forward and report details of the incident.
“Whether this was done willfully or negligently, it is an offence under the Protection of the Environment Operations Act 1997,” council officer Emily Catt said.