from Deb Jacobson of the Printers’ National Environmental Assistance Center
Ms. Jacobson writes: The formulations for inks were modified MANY years ago to reduce or eliminate pigments that contain heavy metals (particularly lead). Cardboard is typically printed with water-based flexographic inks and the adhesives used to make the cardboard are water and corn starch based. Basically you could ingest it for extra roughage if you so choose (as do the bunnies).
The newsprint is typically printed with oil-based offset inks (most common) or water-based flexographic inks and low grade paper. The paper grade used for newspapers is a good thing because they have used less bleaching chemicals and less processing to make the paper. The same is true for the corrugated.
I would suggest you withhold the slick paper, multi-color ads. The newsprint with black ink or newsprint with a few pages of colored ink is fine. One reason is the paper they use may be a higher grade (more bleaching chemicals used). The other reason is the pigments in the colored inks. Some pigments still contain compounds of chemicals that I would not want my “baby” to consume.