Labor Code 6310 protects employees for making complaints regarding the safety of a workplace. If it would be unsafe for an employee to come to the workplace because of a health condition that may be exacerbated by COVID-19 exposure, it would be important to indicate in writing to the employer that they believe it would be unsafe to enter the workplace currently. Expressing this concern is an protected activity such that retaliation for having raised the safety concern is prohibited by law.