Cal. Gov. Code § 3119.5

Notwithstanding Section 3118, any state or local agency that chooses to utilize volunteers shall implement a policy whereby no person aged 60 years or older may be excluded from volunteer service if the person is physically, mentally, and professionally capable of performing the services involved. A person shall be deemed professionally capable if he or she can demonstrate reasonable proficiency or relevant certification and performs his or her professional duties in accordance with laws, regulations, or technical standards governing his or her area of volunteer responsibility.