I use ground coconut husk like Bed a Beast or Eco Earth in most of my pets' enclosures but newspaper or paper towels in the hospital tanks I set up for rescues and recent post-ops. It's illegal to use toxic inks in newspapers in most states in the US, they must be soy based without formaldehyde, toluene and I forget what other nasties. Not sure if the same protections apply to the Canadian papers.
The masthead which lists all the editors, managers, telephone numbers, etc. often states whether soy or traditional inks are used in US papers so you can check to see if your local newspaper is safe.
The Zombie Mama is here!