Any company with 50 or more employees is required to comply. Number of employees is determined by counting employees at all work sites, regardless of location or part-time status. An employer that employs fewer than 50 employees may not be subject to the requirements of this subsection, if they can prove that such requirements would impose an undue hardship by causing the employer significant difficulty or expense when considered in relation to the size, financial resources, nature, or structure of the employer’s business. There are some additional exemptions, and some states have more rigorous requirements; to find out if your company is required to comply, click here.