Ducks were the cause of the commotion at Lake Alexandra on April 18.
A member of the public had noticed the birds had damaged a protective boom in the water, and called Fire and Rescue.
HAZMAT Shellharbour officer Gary Power said the boom had been placed in the lake about three weeks ago.
“There had been a leak at a local service station, and we placed the boom in the water as a precautionary measure, just in case any of the liquid flowed into the lake from the storm water drain,” he said.
“The ducks have pecked away some of the material, so we’re here to clean it up.”
Alongside the HAZMAT Shellharbour crew were Mittagong and Goulburn Fire and Rescue crews.