For things like polystyrene plastic, we are currently relying on the public data (ecoinvent), so I would refer you to their documentation as to how they handle leaks during production, etc.
There was mention in an earlier post about large releases in the D stage for plastic insulation. This is a worst case assumption for landfilled product to make sure all possible residual blowing agenda emissions are reported. If the product is landfilled without extensive grinding, the blowing agent could remain trapped and continue to diffuse at a very slow rate. There have been initiatives in Europe where landfill regulations provide additional drivers to promote recycling opportunities to recover polystyrene, blowing agent and HBCD. Unfortunately, it looks like even with regulatory drivers, they weren’t profitable enough to stay in business. https://polystyreneloop.eu/ With the (lack of) landfill regulations in the US, it is challenge to develop the infrastructure to get materials like polystyrene or fiberglass back to be able to use in new products. We use a lot of recycled glass cullet and some recycled polystyrene, but run into challenges of reliable supply.