Weeks after MyNewtown revealed oil was leaking into the River Severn, close to the town centre, officials are now urging anyone with oil heating to check their tanks and pipes for leaks.
A substance that people described as a diesel smell, along with a oily film on the surface of the river, has been spotted for nearly two months. It appears to be coming from the Dolfor Brook which feeds into the Severn close to the scout hut off Park Lane.
Last week the Mid and West Wales Fire and Rescue Service was also involved in trying to track the leak.
Now, Natural Resources Wales has asked residents and property owners with oil-fire heating to check their tanks and pipes.
NRW are urging any resident or business owners who find a suspected leak to report it to the Incident Control Centre on 0300 065 3000.