Prusa’s flame-retardant Prusament (e.g., PETG V0) has an official UL certification for flammability (UL94 V-0). However, that certification is expressly limited to parts printed under specific conditions:

Printed on Original Prusa MK3S+, MK4, or XL

With a 0.4 mm nozzle and the exact approved profile in PrusaSlicer

Layer heights and sample geometries must follow the tested recipe

Only prints > 0.75 mm wall thickness qualify under the tested protocol Original Prusa 3D Printers+1

Because UL tests the entire printing process, including the printer itself and the way parts are made, the certificate only legally applies to that exact setup — not other machines or profiles, even if the material is identical.

Are the CORE One and CORE One L going to be certified for it as well, and what kind of timeline are we looking at in that case?