An employee may be separated for ongoing medical or disability reasons when he cannot perform the duties of his position due to physical or mental impairment, is not released to work by his health care provider or treating Worker’s Compensation physician, and when all avenues for alternate placement and accommodation under the American’s With Disabilities Act have been exhausted. In all cases, such separation must be supported by medical evidence acceptable to the Director of Human Resources. The City may elect to require a medical examination at its expense and performed by a physician of its choice.