An investigation is to be opened after a firm's nitric acid leak may have put families at risk.

Spen Valley ward councillor Harry Fox called on Hays Chemical Distribution in Gomersal to look into the leak, which released vapour into the air and threatened to pollute nearby water courses.

People living near the plant at Union Mills in Oxford Road were ordered to stay indoors and keep windows closed by police on Saturday as firefighters wearing chemical suits worked to contain the spill. Coun Fox, who spoke to fire chiefs at the scene minutes after the leak began, said equipment and procedures needed to be checked to ensure the safety of residents.

"It's worrying when things like this happen, we have seen it happen before at other sites," he said.

"I hope it doesn't happen again and I trust the company will take measures to ensure it won't."

Emergency services from across West Yorkshire were scrambled to the site after a new container, holding 1,000 litres of concentrated acid, leaked across a courtyard.

The first spillage was around 11am and 40 minutes later a vapour cloud rose from one of the plant buildings as firefighters neutralised the acid with soda ash.

More than ten fire appliances and a chemical spillage unit were mobilised. Police cordoned off Oxford Road at the junction with Quarry Road, diverting traffic.

Two workers were taken to Dewsbury District Hospital after breathing in fumes, but later released.

Station officer Eric Bottomley said: "We were lucky it was so calm, otherwise the spill could have been dangerous to people nearby. Nitric acid is a very powerful chemical and it gives off fumes. If people had breathed it in they would have been in hospital.".

Managing director of Hays Chemicals Steve Holland said an investigation would be made into the cause of the leak, which had come from a brand new container.

But he claimed the spill had not posed a danger to the public.

Resident David Regan, 36, said: "It's never happened before but it only has to happen once."

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