Accidental scenarios in the loss of control of chemical processes: screening the impact profile of secondary substances

The “secondary substances” that may be formed and released as a consequence of “out of control” conditions in a chemical system may be very different, and possibly more hazardous than the substances originally present. These aspects are frequently overlooked in the design and assessment of industrial plants. No robust and widely accepted method currently exists for this kind of analysis. The current contribution develops a systematic procedure for the screening of hazards due to compounds generated and released in accidental conditions. The methodology is based on the assessment of the toxicological, physical and chemical parameters of the compounds, which gives a representation of the inherent “hazard footprints” of the sub-stances. If coupled with experimental protocols, the procedure allows the prediction of potential hazardous accidental scenarios. The validity of the developed screening approach was proved through the analysis of chemical systems where this type of accidents actually occurred in the past.