Incidents due to chemical reactions have, fortunately, been relatively infrequent and “below the radar” over the last few years but the shocking death toll at the Currenta waste treatment facility in the Chempark Industrial Area in Leverkusen on 27th July 2021 is a stark reminder of the huge potential of such incidents. Tragically, seven people have lost their lives in the incident which, according to initial investigation findings, was “probably due to spent liquid in a waste storage tank self-heating rapidly, resulting in an increase in pressure that the tank could not withstand” (

Significant hazards exist in many chemical reaction processes due to exothermic heat release, gas formation and / or thermal decomposition. In manufacturing companies performing “intended” reactions, the characteristics of desired reactions are typically well understood and appropriate mitigation measures are (usually, but not always) in place. In the waste treatment industry, however, the variability of waste and the sheer number of components in the waste creates a unique challenge in reliably assessing and avoiding chemical reaction risks.

Etchells, et al, review of incidents at waste treatment facilities in the UK in 2008 indicated, at that time, a reportable incident frequency of around 10 incidents per year in the UK with nearly 70% of incidents linked to six specific types of hazardous chemical interactions. Whilst the majority of incidents occurred at the waste producers site, a quarter occured at waste treatment facilities.

Effective and efficient waste receipt and bulking compatibility assessment (sometimes involving rapid diagnostic testing) is key to identifying and mitigating risks.

At DEKRA, we offer unique expertise in the assessment of reaction hazards through provision of testing, consulting and training services. We specialise in waste treatment chemical reaction risks and wrote current HSE / Environment Agency guidance on waste compatibility testing in 2011 and published a conference paper at the IChemE HAZARDS XXII conference on waste compatibility testing.

We have upcoming training on chemical reaction risks in our live and online “Design, Development and Scale-Up of Safe Chemical Processes and Operations” course from 4th – 8th October 2021 (view here). This course can also be provided “in-company”. A specialist, one day, in-house training course on hazards of waste treatment facilities – specifically designed for waste handling facilities – is also available. Please contact me for more details or support on the topic.