If you have the time... the National Forest Service may have an answer... but vague for Private Citizens, who may want to assist in cleaning NFS or BLM campsites and trails being... as NFS Cooperators.
I discovered, as one State Employee of a group writing Rules and Regulations for a State's OSHA Bill, the details can be massive... using references. Much like the Forest Service's: FSM 1580.5 and FSH 1509.11 section 91.2 adding reams of additional Rules and Regulations. (Defining a Cooperator with Question 4 on the above website.)
Chain saw injuries are the most 'wicked' a doctor will try to fix. One glance and the physician knows what happened. I never investigated an actual lumber man injuring himself with a chainsaw. Those I did... were 'cut tree hangers', one or more trees cut and hung up in standing timber... later to fall down and crush the chainsaw operator.
A chainsaw is wonderful tool in experienced hands. If you are a newbie... it can detach a limb... alright... your hand and foot in less than a second. Take a class or have an experienced operator show you how to SAFELY operate a chainsaw. A limb is a terrible thing to lose... yours, not that scrub oak being trimmed.