Yes it is. If it has a flame maintained against it, it will eventually catch fire and burn like wood. While we appreciate that this isn’t what everyone would like, it is essential to the overall sustainability of our recycled plastic as adding a fire retardant would mean that it could not melt and therefore be subsequently recycled at the end of its life.
(As per the criteria of UL94 horizontal burn test, our recycled plastic has been classified as HB, which is an equivalent of BS EN 60695-11-10:- Part 11-10: Test flames — 50 W horizontal and vertical flame test methods.)