A tanker that crashed into a river in west Wales, spilling thousands of litres of milk and turning the water white, has now been recovered.
The milk tanker came off the road and into the River Dulais, near Llanwrda in Carmarthenshire, at around lunchtime on Wednesday.
Natural Resources Wales said there had been "significant discolouration" along the river after the tanker spilt its load, and that there had been fears for the local wildlife.
In an interview with ITV News, Natural Resources Wales team leader Ioan Williams said experts were initially "really concerned".
"Milk is one of the worst things that can end up in the river, because it takes the oxygen out of it, which means that fish and other aquatic life can't live," he said.
"It's seven times or so worse than cattle slurry - so it's pretty bad."
Mr Williams said that despite initial fears, no fish appear to have been harmed.
"We monitored the river first thing this morning," he said.
"Our fisheries staff have been out and had an in-depth look at the affected stretch. Thankfully they didn't find any dead fish, or fish in distress.
"Our biologists are coming out in the next day or two and they will take a closer look at whether there's been any impact on the invertebrates - the bugs that live in the river."
Mr Williams said they hoped not to see any lasting effects from the spill, but said it could have been "an absolute catastrophe" on a hotter day.
"Thankfully it happened at this time of year when the river temperature is still quite cold, which means the oxygen levels are slightly higher," he said.
"If this had happened, say, in a drought in the middle of summer with high temperatures, it would have been much, much worse.
"It's not something we see in water courses very often, but when we do it's bad news."
In an updated statement on Thursday afternoon, Natural Resources Wales confirmed the milk tanker had been removed from the crash site.
A spokesperson said: "Officers have been on site this morning and confirm that the river Dulais is now clear and there is no evidence of dead fish to date.
"The milk tanker has been recovered and removed from the crash site. The ‘slug’ of milk is now making its way through the catchment and has cleared Llangadog and is currently in the main Tywi, downstream of Llandeilo, causing local discolouration.
"Milk pollution is very damaging to a river and its habitats, and NRW officers are continuing to assess and monitor the impact of this spill."