A pollution-hit pool at a Black Country Nature Reserve was today being treated after more than 100 fish were killed by contamination.

The Environment Agency started work at Fens Pool Nature Reserve in Brierley Hill his morning.

Dozens of fish were killed by a freak chemical spill following a fire at nearby Wallows Industrial Estate. The dead fish have since been removed by Dudley Council wardens.

Today’s initial project is part of a programme of works to improve the quality of the water following the leak so fish can be reintroduced.

The pool was contaminated when water used to tackle a severe blaze at a biofuels plant on the Wallows Industrial Estate ran off into the reserve.

David Whitford, Black Country team leader for the Environment Agency, said oxygen levels in the water had dropped due to the spill. “We are pumping hydrogen peroxide – an oxidiser – into the pool as there is very little oxygen in there,” he said.

“After this it will be a case of wait and see. We may have to do it again.”

Mr Whitford added the Environment Agency may be able to help restock the pool in due course if asked.

Fire crews called to the factory fire in January built a makeshift dam to try and prevent water which had been contaminated by the biodiesel reaching the reserve. The operation was originally hailed a success but it later emerged one of the reserve’s pools had been polluted.

Two factories which store biodiesel were gutted in the blaze at Wallows Industrial Estate in Fens Pool Avenue earlier this month.

Police are treating the blaze as arson.