We use them all the time, just break off a small piece instead of using the whole log and pile regular wood on top. Wait about 30 min after lighting to roast marshmallows to allow most of the chemical to burn off. It will be fine, its just like when you use lighter fluid to light a charcoal grill.

I would not advise it... there are chemicals and carcinogens in the processed wood that makes using for cooking unsafe, I am certain if you read the label, it will say not for cooking use... but if you want to burn them outside and not make marshmallows, should be fine..

Some manufactured logs have a glue type Binder in them, check the product label if it has a Binder, if so then not for cooking, some logs are pressed together only with no binders.