Even for those not partaking in marijuana, the various California laws regulating its use can be confusing – particularly for employers.

The trend in state legislatures to permit the recreational and/or medicinal use of marijuana began with California’s Compassionate Use Act in 1996, which allowed state residents to use the drug for medical purposes and decriminalized possession of less than 28 grams. Complicating the matter, however: marijuana use remains prohibited by federal law.

With limited use of marijuana legal in the state, how can employers find out about a worker’s use of the drug or limit it without running afoul of state law?

Employers have two options, either try to get their hands on historical information, such as criminal convictions, or seek out current input via drug testing.

Criminal history related to drugs in many instances is off-limits for employers. Job applicants cannot be required to disclose an arrest that did not result in a conviction or participation in a pretrial or post-trial diversion program. Any criminal history that has been expunged, sealed, or dismissed will be unavailable as are marijuana-related convictions dating back more than two years.

While California has not banned the box for private employers, local jurisdictions such as San Francisco have, requiring employers to wait until after a live interview or determining that an applicant meets the qualifications for the position before inquiring into criminal history. Background checks – whether performed in-house or by a third party – require compliance with federal law (the Fair Credit and Reporting Act (FCRA) as well as California’s counterpart, the Investigative Consumer Reporting Agencies Act (although the legality of the state statute is unclear, see story below for more detail). And such investigations into applicants’ history are a current target for the Equal Employment Opportunity Commission – which has filed multiple lawsuits (http://www.scherzer.com/eeoc-loses-again-in-challenge-to-background-checks/) against employers alleging their background checks constitute disparate impact discrimination against protected groups like African-Americans – and a popular basis for class actions. Recent cases have settled with multi-million awards, including a $2.5 million payout by Domino’s Pizza and a $6.8 million deal between Publix Super Markets and a class of applicants alleging the company violated the FCRA.

Drug tests can be viable option for employers. Once a job offer has been made, an employer may require an applicant to pass a drug test as a condition of employment (as long as all potential employees are subject to the same requirement). After a worker has been hired, drug tests may be used if an employer has a reasonable suspicion that the employee is under the influence. Certain jobs – such as those in the transportation industry like truck drivers – may permit such testing more freely. If a test comes back positive, employers do have the discretion to discipline, terminate, or choose not to hire an applicant even if the individual legally holds a medical marijuana card issued by the state. In addition, despite the requirements under the Americans With Disabilities Act and California state law to provide reasonable accommodations to employees considered disabled, neither federal nor state law requires employers to permit marijuana use as such an accommodation.