Storm Lake officials are working to determine the cause of a leak in dredge equipment at the Storm Lake marina.
Tuesday, the city pumped more than 500 gallons of oil out of the hydraulic system so heat exchangers on the dredge could be removed.
The two heat exchangers are being examined and may be sent to a Story City shop for inspection and any needed repairs. Removing the equipment appears to have stopped the leak.
If no leaks in the heat exchangers are found, the city will continue trying to identify the source of a leak that was first reported on March 10. City officials have placed booms around the dredge and used sphagnum moss to absorb oil.
The leaked oil is vegetable-based, not petroleum-based, but as it decomposes it uses oxygen in the water. Large spills can cause oxygen levels to drop in the water affecting fish and other aquatic life. At this time, no impact to fish or aquatic life has been observed.
The Iowa Department of Natural Resources (DNR) will continue to monitor cleanup activities.