I do it on top as a mulch layer for water retention, and natural weed barrier outdoors for my veggie garden and see no issues, gorilla ganja....
Id be adding roughly 3 gallons to a 2ftx4ftx18inch bed and mixing it in to the soil its self.... I was thinking of using it to add a carbon source for future bed life, to help with microbial and fungal life, water retention/aeration and just to use up the bag of wood chips up sonce they have been in the garage for a year!!
I believe they are pine and very thin used for rabbit or dog house bedding. I do know some types of wood are more harmful then helpful.
Im more curious as to how much nitrogen they steal as I've read numerous stuff from the world wild web... I figure if i add an extra cup or 2 of something like a blood meal to compensate for the leaching of nitrogen it balance out for the time being.