Only employers that carry 50 or more employees at a worksite, or within 75 miles, are covered by the FMLA. However, for an employee to be eligible, he or she must have worked for the employer for at least one year and must have worked at least 1,250 hours (an average of 25 hours a week) during the previous 12­month period. An employer may deny leave to any key employee who receives a salary in the top 10% of the work force and whose leave­taking would cause economic harm to the employer.