D.C. Code § 38-2001.04
Any teacher who shall have reached the age of 45, and who shall have been continuously employed in the public schools of the District of Columbia for not less than 10 years immediately prior to his retirement, or who shall have been continuously employed for not less than 15 years prior to his retirement and who by reason of accident or illness not due to vicious habits has acquired a physical or mental disability and is incapable of satisfactorily performing the duties of his position, may be retired by the Board of Education under the provisions hereinafter stated; provided, that absence of any teacher on authorized leave of absence without pay for a period not in excess of 2 years shall not constitute a break in continuous employment; provided further, that no teacher shall be retired by the Board of Education under the provisions of this section until said teacher shall have been examined under the direction of the health officer of the District of Columbia, and as a result of said examination, in his judgment, or in the judgment of two-thirds of the members of the Board of Education shall have been found to be physically or mentally incapacitated for efficient service.
D.C. Code § 38-2001.04