THE £80 million upgrade of Oldham Wastewater Treatment Works has been halted after residents complained of breathing problems as a result of a pungent ammonia smell.

Environmental health officers from Oldham Council have stepped in to stop contractors working after being contacted by worried families in Foxdenton Lane, Chadderton, which backs on to the site.

Some of the residents have visited their GPs and local walk-in health centres to access treatment.

The back gardens of about 20 semi-detached homes back on to the site where a 15 metre mound has appeared during excavations for a new pipeline between Chadderton and Royton sewage treatment works which is being decommissioned.

The project has been ongoing for three years, but residents started noticing a bad smell in February.

“It’s so bad, we can’t go into our back gardens without being overcome with fumes,” said Kay Lomas, aged 48.

Mrs Lomas, her husband Stephen, 58, and their 10-year-old son Matthew had visited their doctor complaining of breathing problems, but were told there was not treatment of it other than for the smell to go away.

“I have contacted the council’s environment health team and when an officer visited, he couldn’t stand it in the back garden for longer than two minutes,” she said.

Neighbour Lincoln Barrett, 49, told The Oldham Times: “I went down the alleyway down the side of my house towards the back garden and the smell made my eyes water.”

He said his wife Nicola had also been badly affected by the ammonia odour.

Mum Sarah Newton, aged 32, lives a few doors away with husband Steve, also 32 and daughter Freya, seven, and Poppy, four.

She said: “We’ve been to the walk-in centre to see if we could get anything, but I’ve resorted to using my husband’s inhaler.”

A spokesman for Oldham Council confirmed environmental health officers had visited the site and ordered contractors to stop work, which they have done.

“We’re having a meeting about the problem with United Utilities and the residents have been informed of this.”