California Department of Public Health
Isolation and quarantine are two ways public health authorities can contain the spread of a disease. Both are common in public health, and both aim to control exposure to infected or potentially infected persons.

Workplace Settings: Need to follow Cal/OSHA requirements pertaining to this new Isolation and Quarantine Guidance from CDPH
In the workplace, employers are subject to the Cal/OSHA COVID-19 Prevention Emergency Temporary Standards (ETS) or in some workplaces the Cal/OSHA Aerosol Transmissible Diseases (ATD) Standard (PDF), and should consult those regulations for additional applicable requirements.

Schools
For quarantine considerations in K-12 school settings, see Safe Schools for All Hub