Campagners for the environment have pledged to oppose a multi-million pound waste-fired energy plant planned for Severnside.

Recycling and waste company Sita UK wants to build the waste-to-energy facility on a 20-acre brownfield site next to the Seabank power station between Severn Beach and Avonmouth.

If given approval, it would generate enough power for 50,000 homes by burning up to 400,000 tonnes of commercial and industrial waste every year.

Sita said the kind of material fuelling the plant would otherwise go into landfill sites.

But the organisation Friends of the Earth said it would be "vigorously opposing" the plant.

Its members fear it will pollute the air with dangerous chemicals and prevent recycling, arguing there were better options for disposing of waste and generating electricity.

It alleged the pollutants released from such plants presented an unacceptable risk to health, despite European Union limits on the emission of dioxins – a group of chemicals linked to cancer.

Alan Pinder, of South Gloucestershire Friends of the Earth, said there was no safe dose for dioxins and claimed incinerators also produced large amounts of carbon dioxide and other air pollution.

He said: "Incineration is a cheap and dirty option for disposing of waste. Sita has put a lot of effort into selling this incinerator as a green option, which it isn't.

"Although the proportion of dioxins will be small, it will be such a giant incinerator that the quantity of dioxins will be totally unacceptable. If it goes ahead, we will be breathing these toxic gases for the next 30 years.

"Recycling and digestion are the green, clean options but they need more effort. Local councils are doing a good job in recycling household waste but business has been very poor. If they have the option of burning everything in this incinerator, why would they recycle?

"Any waste incinerator needs lots of paper, card and plastics because otherwise there is nothing to burn. We should be recycling paper, card and plastics, not burning them."

Sita already operates plants elsewhere in the country and if the Severnside complex is approved, it will be Sita's first in the South West.

Gareth Phillips, Sita's planning and property manager, said: "I understand Friends of the Earth's position but this is a facility that stands alongside recycling.

"It's aimed at dealing with materials that are not recyclable."