Angry residents claimed they were “left in the dark” about emissions from a ceramic tile plant approved for Rutherford.

Heather Berry and Sandra Smith said they were shocked to find out hydrogen fluoride and heavy metals would be released into the atmosphere from the multi-million dollar project – even after they were told the only residue would be water vapour.

Both women said they attended a public meeting last year with the proponents of what has been proclaimed the biggest plant of its type in Australia.

No mention was made of the emissions – which also include traces of sulphur dioxide and nitrogen oxides – Mrs Berry said.

“They quite clearly stated that there wasn’t any,” she said.

“We were led to believe that here was a clean, green industry with no potentially harmful emissions.”

National Ceramic Industries Australia Pty Ltd spokesman Hilton Gruegon said there was no deliberate attempt to conceal anything.

“None of that was detailed at the public meetings because they weren’t significant,” he said.

“The main emission is the water vapour from the kilns.”

Mr Gruegon said the plant required approval from the Department of Infrastructure, Planning and Natural Resources and the Environmental Protection Authority.

“This has been handled at the proper levels,” he said.

“It wasn’t something that was slipped through.”

Minister for Infrastructure and Planning and Natural Resources, Craig Knowles, approved the proposal on July 2, subject to a rigorous schedule of conditions.

One of those conditions was that the maximum allowable level of hydrogen fluoride discharges was 5mg per cubic metre.

Hunter Region Environmental Protection Authority (EPA) regional manager Michael Kerr said the NSW standard was 50mg per cubic metre.

“The level for the Rutherford plant is 10 times less than the regulation,” Mr Kerr said.

“There’s not going to be any effect on humans directly.

“There may possibly be an impact on vegetation and the company is required to undertake a monitoring program.”

Mr Kerr said the emissions would not affect sensitive vegetation areas such as vineyards because they were too far away.