A SERIES of highly toxic emissions from Scotland's newest waste incinerator in breach of safety limits are threatening to upset plans to build similar controversial plants across the country.

An energy-from-waste plant at Dargavel in Dumfries has had its operations restricted by the Scottish Environment Protection Agency (Sepa) after it admitted releasing cancer-causing dioxins up to two-and-a-half times permitted levels into the air.

The company that runs the plant, Scotgen, is now facing difficulties obtaining a pollution permit for a second waste incinerator at Dovesdale Farm, near Stonehouse in South Lanarkshire. This proposal has prompted 24,000 objections from local residents and others concerned about the health risks.

Scotgen's problems are also likely to hamper plans by other companies for another 14 incinerators across Scotland. Most of them have run into fierce opposition from local communities.

Scotgen's Dumfries plant, commissioned in 2009 to "gasify" more than 20,000 tonnes of hazardous and municipal waste a year at high temperatures, has had a troubled history. Its pollution performance has been condemned as "very poor" by Sepa.

Before the plant was shut down in April 2011, it suffered some 200 breaches of emission limits, two of which were because of dioxins. According to Sepa, it also had 100 "short-term exceedances" and prompted 45 noise complaints.

Problems began again soon after the plant was restarted towards the end of March this year. On May 29, it emitted 0.25 nanograms of dioxins. The permitted limit is 0.1 nanograms.

Sepa ordered that the offending boiler be closed down while the breach was investigated. During trials in June there were a further two dioxin breaches. After further investigations, the plant was allowed to restart last week.

Dioxins are a group of highly dangerous and persistent pollutants produced by combustion. As well as triggering cancer, according to the World Health Organisation they can cause reproductive and developmental problems and damage the immune system.

Sepa told the Sunday Herald that it would not grant a pollution permit for Scotgen's Dovesdale plant until it received "key information to demonstrate the viability of the technology" in Dumfries.

According to Sepa, Scotgen has also had financial difficulties. The company was sold just before its previous owners, Ascot Environmental, went into administration on May 18, 2012.

John Young, from the Action Group Against the Dovesdale Incinerator, urged Sepa to shut down Scotgen for good. "This company has a failed track record in protecting both the environment and public health," he said.

Scotgen confirmed there had been dioxin breaches in Dumfries, but pointed out that Sepa had approved the restart of operations last week. "Scotgen is continuing to work closely with its regulator," said the company's director, Lloyd Brotherton.