No. Asking an applicant for employment whether he or she smokes would be considered a health-related question and is prohibited during the application process.
Under the Americans with Disabilities Act (ADA), an employer is prohibited from asking health-related questions before extending an offer of employment. Once an offer of employment has been made, an employer may condition it upon the successful completion of a medical exam.
Note: If an employer requires a medical exam, the exam must be job-related and applied uniformly to all applicants, or categories of applicants.
As a practical matter, whether an applicant smokes is irrelevant for most employers. Under state law, smoking is prohibited at place of employment, with limited exceptions (Labor Code Section 6404.5). Therefore, regardless of whether an employee smokes, the employee is not allowed to smoke in the workplace.
A common employer complaint is that employees often disappear during the workday and/or take extended breaks to smoke. Employers who have a problem with this type of absence can limit smoking to breaks and meal periods.
For more information, see Smoking in the Workplace in the HR Library.