It's way easier to eliminate nuts being in or near the production line of a food product than it is to remove every single bone from something that inherently has bones, but even then:

> The Nut Free labeling means the product does not contain nuts. However, it doesn't guarantee the snack was made inside a dedicated nut free facility. Whether or not the nut free product was created on the same production line as a non nut free snack, is unknown.

https://www.nutfree.org/different-kinds-of-nut-free-labeling...

the label doesn't mean the process it was made was completely immune from contamination.