High dioxin emissions force closure of Castle Cement kilns

Castle Cement’s Padeswood cement works in North Wales was by far the UK’s biggest source of dioxins in 2004, according to data from the Environment Agency. The company has now confirmed that it will shut down the site’s three old cement kilns by the end of May.

Cement works have provided a severe test of public confidence in both the industry and Agency regulators. Controversy over operators’ plans to use waste materials as fuel has spilled over into general concern over pollution from the sector.

Problems at the Padeswood site have been compounded by a lengthy delay in plans to construct a modern, more efficient kiln. This is intended to replace the three ageing kilns at Padeswood, and another two at Castle’s controversial Ribblesdale site.

At both sites, the Agency accepted Castle’s argument that significant investment in upgrading the old kilns was not justified. As a result, the Ribblesdale site has continued to cause problems from odour and plume grounding (ENDS Report 354, p 13 ).

The old kilns at Padeswood have also run for many years longer than expected. Castle originally wanted to shut them in 2001, but a public inquiry into planning permission delayed progress with the new kiln. It is now likely to be commissioned later this year.

In March, the Environment Agency served an enforcement notice on Castle’s Padeswood site requiring it to stop operating kiln three after monitoring data submitted by the company showed massive breaches of its emission limit for dioxins (ENDS Report 362, p 10 ). The breaches were recorded last year, but not notified to the Agency until 21 February.

The site’s integrated pollution and prevention control (IPPC) permit set a limit for dioxins from kiln three of 1ng/m3. However, four spot samples of dioxins conducted by Castle in October and December found emissions levels ranging from 23-56ng/m3.

Monitoring also found significant breaches of the 0.1ng/m3 limits which apply to the two other kilns on the site. Dioxin emissions were found to range from 1.7-4.6ng/m3.

The Agency estimates that the total release of dioxins from Padeswood in 2004 was 23g, expressed as a toxic equivalent. This represents a dramatic increase - data on the Agency’s pollution inventory put dioxin emissions from the site at 0.9g in 2003 and 0.3g in 2002.

Last year’s emissions from Padeswood contrast with the 38g released by all Agency-regulated sites in 2003. The main sources in 2003 were Corus’ steelworks at Port Talbot and Scunthorpe which each emitted 9g.

More recent tests by the Agency and Castle, carried out in February and March respectively, found that breaches on kilns one and two are continuing, with levels ranging from 0.24-1.2ng/m3. However, the Agency decided to allow these two kilns to continue in operation.

Agency officer Jim Morris said it was a "moot point" whether the Agency should require Castle to shut kilns one and two. He accepted that IPPC permit limits are being breached, but suggested that there is not a risk of "serious pollution".

Castle’s IPPC permit allows it to operate the kilns for up to a year after commissioning of the new kiln. However, as a result of the dioxin data the company has agreed not to restart kiln three and to close kilns one and two by the end of May.

Data on dioxin emissions confirm that the pollutant has been a long-running issue at the site. Kiln three has been the main source of the problems, with monitoring finding a wide fluctuation in dioxin levels.

According to Jim Morris, in 2001 the Agency lost patience with the company’s inability to reduce emissions. It issued a variation notice giving Castle six months to meet limits of 0.1ng/m3 on kilns one and two and 1ng/m3 on kiln 3. Prior to this, there had been no limit on the site’s dioxin emissions.

As a result, Castle fitted spray-cooling equipment to kiln three, at a cost of around £100,000. This appeared to be successful in reducing dioxin emissions - until recently.

Neither the Agency nor Castle would comment on the cause of the recent breaches. The Agency is investigating the incident and has not ruled out further enforcement action.

In a statement, Danny Coulston, general manager of the Padeswood works, said: "Castle Cement has been unable to replace the older and less efficient kiln three as quickly as it would have wished because of severe delays caused by the planning inquiry for kiln four. Castle has always viewed the solution to the high dioxin emissions at Padeswood as the installation of kiln four. Proposals for the new kiln were discussed with the Agency in 1996 and the proposals announced in 1998. It is unfortunate that planning delays mean that kiln four will only start operating this year."

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