From my readings I have found out that red and black mulch is treated with arsenic and other chemicals to repel bugs. Cocoa mulch is especially dangerous to dogs of course.
So far it seems plain bark mulch or pine mulch is the safest.
If you are trying to just stop weeds have you tried shredded newspapers? It may not be as attractive but it is much safer.
Assumptions do nothing but make an ass out of u and me.
We can stick our heads in the sand for only so long before it starts choking us. Face it folks. The pet population is bad ALL OVER THE WORLD!