If the answer to an issue is not here and you want to know more than telephone us on +44 1902 373365 USA and the Environmental Protection Agency (EPA) proposal to classify fly ash as a Hazardous Waste - March 2010 On 22 December 2008 at 1.00 a.m. in the Tennessee Valley, USA near Harriman, Roane County, suffered the failure of a sixty foot earthen dam at the Kingston Fossil Fuel power station, containing 4,100,000 m3 of saturated coal fly ash. As a result of this catastrophic accident, the EPA in the USA has proposed re-classifying fly ash (PFA as its is generally known in the UK) as Hazardous Waste. This would be detrimental to the utilisation of fly ash in many different applications. The UK does have a number of lagoons, but these are constructed, inspected and maintained in a totally different manner, thereby rendering the risk of a similar dam failure with the UK as non- existent. Position Paper 3 "The proposal by the EPA (USA) to classify fly ash as a hazardous waste" details the UK position on this situation. The UKQAA fully supports the ACCA (American Coal Ash Association) position that the proposed re-classification would be a disaster for the recycling of coal fired power station products. For further details please see the ACAA web site at http://www.acaa-usa.org/. Exploding Foamed Concrete - November 2009 - Updated February 2011 Update February 2011 - Further to the above incident it is understood that changes have been made to the production of Incinerator Bottom Ash to resolves the problems. For further information the HSE and Ballast Phoenix web sites should be consulted for details, see http://www.hse.gov.uk/construction/liveissues/foamedconcrete.htm and http://www.ballastphoenix.co.uk/. During November 2009, an incident occurred where foamed concrete exploded due to a hydrogen gas build up. This explosion injured two workers. It is our understanding that this incident was a result of inclusions of elemental aluminium within the Incinerator Bottom Ash (IBA) being used as a coarse aggregate. These particles of elemental aluminium as we understand result from metal in the waste stream, such as aluminium foil, being intimately mixed with other wastes and the linear magnetic removal systems not being able to extract it prior to burning. The result is flecks of elemental aluminium are present in the IBA. The reaction in the foamed concrete of elemental aluminium and calcium hydroxide produced hydrogen gas, which is the same reaction as used in the manufacture of aerated concrete blocks – this reaction is nothing new. In normal use the hydrogen gas with adequate ventilation will quickly disperse and pose no risk, however, if the hydrogen gas is trapped in a confined space in sufficient quantities it may result in an explosion taking place. Aerated concrete blocks production use this same effect to produce their cellular structure, here the elemental aluminium is added as a very fine powder. The resulting hydrogen gas produces the lightweight, cellular structure required for such blocks. Any residual hydrogen is removed during the autoclave process, so aerated blocks do not represent any risk to the user.