Toxic pollution breaches and an explosion at a new Scottish waste incinerator have triggered tough legal action and an investigation by Government safety watchdogs, upsetting plans for a dozen more waste-burning plants.

The Sunday Herald can reveal that the Scottish Environment Protection Agency (Sepa) last week slapped an enforcement notice on Scotgen, a company trying to commission a pioneering "energy-from-waste" plant at Dargavel in Dumfries.

This follows an admission that the plant breached safety limits by emitting more cancer-causing dioxins than permitted in October, and then failed to promptly inform Sepa. It has been ordered to restrict operations, and ensure that monitoring results are provided as soon as possible.

Scotgen is also under investigation by the Health and Safety Executive (HSE) following a "pipe burst" at the Dargavel plant in August. According to a report, nearby pipework and a roof were damaged by a steam explosion.

Environmental groups and local campaigners say that the plant is dangerous and are demanding that it be shut down. They are calling for plans for other waste incinerators in Glasgow, Lanarkshire, Renfrewshire, Lothian, Perth, Aberdeenshire and Invergordon to be halted.

Scotgen has been trying to get the Dargavel plant to work since 2009, resulting in repeated pollution breaches and breakdowns. It is meant to gasify more than 20,000 tonnes of hazardous and municipal waste a year to produce electricity.

But according to Sepa, emission limits have been broken more than 200 times and there have been 250 other breaches, complaints and issues, resulting in its pollution performance being declared "very poor". Last July, the Sunday Herald reported that parts of the plant were closed down after dioxin emissions exceeded permitted limits.

Despite assurances that the problem was being dealt with, there was another dioxin breach on October 16, which the company failed to report immediately to Sepa. Sepa launched an investigation and on Monday issued an enforcement notice saying that two licence conditions had been breached and action was required.

Dioxins are dangerous pollutants produced by combustion that are subject to strict limits. The World Health Organisation says they can trigger cancer, cause reproductive and developmental problems, and damage the immune system.

"The terrible goings-on at Scotgen's Dargavel plant have reached a new level of farce," said Dr Richard Dixon, former head of WWF Scotland who this weekend becomes director of Friends of the Earth Scotland.

"This new design can't meet its pollution limits, isn't producing meaningful amounts of electricity and hasn't dealt with much waste. Scotgen has had its chance: this plant should be shut down."

Alis Ballance, chair of the Green Party in Dumfries and Galloway, campaigns against the Dargavel plant. "It has repeatedly malfunctioned from the start, exposing local residents to health hazards by releasing toxic emissions far above the permitted levels," she said.

Scotgen, however, argued that calls to close the plant were "misplaced". It maintained that the local community was behind its operations, which supported up to 150 local businesses.

"We are working closely with Sepa in order to address the points raised and actions required, and are confident these will be addressed in the timescales allocated," said the company's managing director in Manchester, Jim Hennessey.

"In the interim, the facility is fully operational as designed in accordance with its permit and is continuing to process waste." Alternatives to landfill were needed, he argued, and Dargavel was "the natural progression".

Hennessey confirmed a "pipe burst" in August had been reported to the Health and Safety Executive. He denied that this had prompted an investigation, saying "the facility is not under HSE investigation".

But this was contradicted by the HSE. "We are aware of Sepa's actions and are involved in an ongoing investigation into pressure systems at the plant," stated an HSE spokeswoman.

The incidents at the Dargavel plant were "clearly concerning", said a spokeswoman for the Scottish Government. She said: "Sepa applies a robust and stringent enforcement policy that minimises any risk to public health or the environment."

This was shown by Sepa's rejection of Scotgen's plan for another incinerator in South Lanarkshire, she said.

"Treating this waste to create energy helps Scotland in its journey toward securing a mix of renewable energy sources, while also creating much needed local jobs," the spokeswoman said.

Sepa agreed that energy-from-waste facilities had a part to play in the management of Scotland's waste. It was reluctant to take the "extreme measure" of closing the plant.

"As it is still commissioning, and the operator continues to make necessary improvements, closure is not Sepa's preferred enforcement option," said a Sepa spokesman.

"However, the operator is being encouraged to finalise commissioning, demonstrate that the plant can comply with its environmental licence and generate power at the earliest opportunity."