To be on the safe side I would. However it is unknown if the toxins will pass from the paper/cardboard into the compost then taken up by your veg. Each process would lose more of the toxins as some would be lost at each stage to the soil and drain away.

If DDT is an example (a much stronger chemical), it was sprayed on insects to control numbers and disease, it was eaten by small birds then larger birds ate the smaller ones. The top of the food chain birds had concentrated levels of DDT that effected egg shell growth so their numbers dropped.

I am not an expert on this but I would have thought that the concentration of toxins would be so tiny that it would give no reason for any concern

Many thanks for this advice. It is what I had hoped to see.

I really wanted to find out what others thought.

I shall go on composting all my cardboard and paper. My plot has little more than one spit's depth of topsoil on London Clay and so I need everything I can get.

I'm with Inverglen on this one, I reckon that any potential toxins would be pretty diluted after composting and there is probably very little danger from using it.

Black ink is normally safe, while colored inks can contain toxic metals that are better avoided.