A fuel leak in the River Taff which killed fish and sparked a warning for people to shut their windows has now stopped, official have said.
Officers from Natural Resources Wales (NRW) on Wedneaday the source of the pollution affecting the Taff in places such as Nantgarw, Treforest and Taffs Well since 16 October over.
GE Aerospace previously confirmed fuel got into the river while repair work took place at its site nearby, but NRW said it was working to determine how fuel entered the drainage system and reached the river.
NRW added it had found fewer than 10 dead fish and impacts to aquatic invertebrates as a result of the leak.
NRW said the source was identified at 19:30 BST on Friday, after kerosene spread down almost 2.5 miles (4km) of the river.
It added evidence was being compiled and reviewed as part of the ongoing investigation.
The environmental body also received reports of pollution affecting the Taff in Glan Y Llyn, Gwaelod-y-garth and Tongwynlais.
