The EFSA Panel on Food Contact Materials (FCM) assessed the safety of the recycling process Starlinger viscotec deCON (EU register number RECYC339). The input is washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are preheated batchwise before being submitted to solid state polycondensation (SSP) in batch or semi-continuous reactor(s), at high temperature under vacuum and gas flow. Having examined the challenge test provided, the Panel concluded that the preheating (step 2) and the decontamination in the SSP reactor (step 3) are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance are temperature, residence time, pressure and gas flow rate. It was demonstrated that this process ensures that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.0481 or 0.0962 μg/kg food (depending on the molar mass of the contaminant substance) derived from the exposure scenario for infants when such recycled PET is used at up to 55% together with virgin PET, and of 0.156 or 0.312 μg/kg food, derived from the exposure scenario for toddlers, when used at up to 100%. The Panel concluded that the recycled PET obtained from this process is not of safety concern, when used at up to 55% in mixture with virgin PET for manufacturing materials and articles for contact with all types of foodstuffs, including drinking water, and at up to 100% for contact with all types of foodstuffs except drinking water, and used for long-term storage at room temperature or below, with or without hot-fill. Articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.